Basic Training - On The Move

Whatever gear, and how much, you think you're going to need, in order for it to do any good, you have to get you, it, and any number of like-minded friends, from Point A, to Point B.

There are a number of ways to do this, but the one that's always going to come into play no matter what, is on foot. Even if you ride, sail, or fly to where you're going, you're going to have to get off the ride at some point.

Once again, everything you need to know to get started is in the reference you should be getting very familiar with, FM 21-18 Foot Marches April 2017.

So, let's say you're going bare minimums:
Your basic clothes 8#
An M4gery, with optic, cleaning gear, and ammunition: 19#
Two quarts of water in canteens: 5#
Food: 1#
First Aid kit: 1#
Means to carry and hang just all that on you: 6#

You're at 40#, now.

Figure a minimal pack: 3#
with more water: 5#
and more food: 2#
and minimal rain and sleep gear, i.e. poncho and liner: 3#
and a change of socks and under wear 1#.

Figure a knife: 1#
and a bare bones EDC survival kit (we'll get to that by and by): 1-2#.

So you're still at between 40-57 pounds of gear, just to leave the front porch for a bare minimum walk, in a single day or overnight, with no resupply nor means to eat or drink beyond 24 hours.

And you're going to walk that.

The only way to build up to that, is to build up to that.
For Common Core grads, a "klick" is a kilometer, which is 0.6 miles, or near enough.
IOW, a 5 km march, for example, would be 3 miles.

You should start, in addition to your daily PT, with putting on a bag or pack, and working up.
For a training period, we'd do this:
Load a small but sturdy backpack with 20# (weigh it!, and water/snacks don't count), and do 3 km. At a brisk pace on level ground. Don't jog, run, or anything more than a very rapid walk.

Time yourself.

At the published average march rate of 4 KPH, you should cover the 3km (1.8mi) distance in 45 minutes. If you didn't make that, you're too slow.
I say again, If you didn't make that, You're too slow.
Either way, you've got a baseline to aim for. Drive the route beforehand, and note the 0.6 mi. increments using your odometer.
If you go outwards 0.9 mi., and go out and back, the 0.6 is 1/3 and 2/3 of the distance, going and coming. You should be there at 15 and 30 minute marks, and the 0.9 mi. turnaround in 22 1/2 minutes, or better, if you're on pace.
(BTW, day-glo orange and yellow spray paint is sold at the local hardware store, and a spot or short stripe at the curb or on a corner of the sidewalk probably isn't going to cause the walls of the citadel or nearby courthouse to crumble into dust. Road and survey crews plus local utility teams do this 24/7/365, everywhere. Just saying.)

Now you know where you stand in terms of basic ability, with about 1/3 of your bare minimum load.

You can probably guess what happens next.

Your new after-dinner activity every day to every other day after this basic training, is to increase the distance and the load, until you're carrying the equivalent of what you'll be packing, and can do so for a full 8-hour period.

Go up by 2KM/week. Do the base distance every evening. Make the weekend march the one where you add that additional 2Km, which is your new starting distance the following week.
During the week, add another pound a day, for a total of 5#/wk., i.e.:
Week 1 20-25#, starting with 20# for 3K and finishing at 25# for 5K.
Week 2 25-30#, finishing at 7K.
And so on.

At that rate, it'll be a month before you're doing almost 10k (6 mi.), with 40#.
(That would be the equivalent of 3 miles out and 3 miles back, in only your stripped-down fighting load, above).
It'll take you 3 months to get to 80# and 15 miles, and 4 months to be able to carry full weight for a full 8 hour march.

And you can stop adding weight when you've weighed your gear, and figured out your max load, and you reach that weight.
Unless you want to plan for the times when you might need to carry more, like an injured comrade, and his gear.
Which would be smart.

Bear in mind this notional training period is a mere two weeks.
Just like now, you'll be on your own a lot more than you'll be under supervision.
Remember what we said before we started about self-discipline?
You can bullshit anyone you want, but you can't bullshit yourself, or Reality.
Do the work or suffer the consequences.
Like you will.

So on your own time, after basic training, you should be shooting for nightly walks of the target distance - under load, and at least one all-day (approaching 8 hours) walk on your day off (Saturday/Sunday/whatever day your week works out), with eventually 60-80#, for 32+km. (33K being 19.8 miles! That's the 8-hour standard to shoot for, since about Hammurabi.) 
If you can carry a loaded backpack during the day, for some or all of it, that would be helpful.

[If you decide to try adding workout weights to your daily routine, make them waist belts or body vests, if not simply a backpack with actual useful items. Do NOT put on ankle weights, unless you want to overstress your lower extremity joints, and put your orthopedic surgeon's kids through college. Ankle weights are generally for idiots and fools: be neither one of those. If you want to start wearing heavier footgear instead, like for instance the various boots you may be walking in every evening, that would be far more intelligent, and also serve to start breaking them in - like you should do.]

And once you're doing 10k or better, it's time to get off the roads and start making your weekly jaunts cross-country, over progressively worse terrain as you may, in any weather rain or shine, and in all seasons.

After your initial pace experiment, you should stop after the first 10-20 minutes every time, to address gear carriage/comfort, and address any hot spots on your feet. Blisters are always easier (and more fun, trust me) to prevent than to treat. Moleskin and Spenco Second-skin blister prevention patches should be your new best friends, as you toughen your body, bones, muscles, and feet, to being able to walk distances under load, slowly and progressively.

This regimen cannot be "crammed". You can't skip the daily work-ups, and try to cram one week into Saturday, or Saturday and Sunday. You'll tear up your feet, joints, muscles, get injured, and have to start all over again from the beginning after you recuperate.

Also, I get that you may not be able to take 3,4 or 5 hours after dinner every night to go on walkabout. That's why I recommend doing some work during the day (even on a lunch break) to fulfill some of the time requirement. Bear in mind as well, you can do it 2-3x a week, plus one weekday, just increase the weight each time without fail, and if you decrease the time you can devote, increase the pace as well as the weight. The weekend walk still need to be the full time/distance and ending week's weight goal.

And remember, this after-dinner training every 1-2 days is for a few months, not your entire life. Suck it up for four months to get to the goal.

This isn't The Devil's Brigade, and you're not an idiot (I hope). You don't need to be toting rocks or sandbags to make up the load. At the start, make it water and useful items: sunscreen, insect repellant, extra socks, foot powder, ACE bandages, etc. one of the Camelbak HAWGs or equivalent is a useful training aid at that stage. Regardless, add weight progressively, then distance, and repeat until you've toughened yourself enough to cut the mustard.

(And if you don't want to scare the shit out of the locals, the constabulary on patrol, and/or get shot, buy a single workout dumbbell of 8-10 pounds, and carry it in your hands to simulate a weapon, whenever you're inside city limits, or in sight of civilization, like public roadways where the local mounties drive and patrol. Holes in your ass and/or time in the pokey is never good training. An 8-10# weight carried out in front of your body, however, is. You can also get a 5-6' piece of blackpipe, cap it, and fill it with an appropriate amount of concrete, and paint it to look like a wood walking stick, and no one will ever care. Ask me how I know. A 3/4" piece weighted at the tips also makes a wicked quarterstaff for self-defense. Just saying.)

Once you're at distance (+/- 20mi.), weight (70-90#), and speed/endurance (8 hrs.), you can cut back to a once-a-week hike on the weekends, provide at least one per month is full weight, full speed, over off-road terrain, to maintain the level of ability you worked so hard to achieve. (You should be continuing to PT regularly, regardless.)
You are free, however, to work out at the exact same standard more frequently than weekly if you choose.
If things get sporty, it'll be your ass, after all.
Do what you think is prudent.

You don't have to like it, you just have to do it.

You're not getting shot at. Yet.
Getting your body in condition is called "sharpening your hatchet."

You should, at this point, read FM 21-18 Foot Marches April 2017 cover to cover, and master it down to the details. Then get busy on the practical portion until your body knows the material as well as your head does.