Something to consider is that these old trucks have very flat and straight frames, modern ones don't. The main problem with that is the hump over the rear axle, to line the bed up right on the outside you tend to look several inches on the inside. It's why many people who do a chassis swap put a flat bed on the back.

There is also the issue of lining up the cab and front clip to be centered with the chassis and powertrain, sometimes this means loosing a lot of foot room inside.

I've looked into doing this for my truck, and talked with a couple people who have done it that way but who also swapped parts. Though I haven't gotten to that point in my build yet, swapping parts is far less of a head ache. Cab placement basically sucks to do on a different chassis. There are members who have done it though, check out Ted's 4x4 '54 :
Ford Truck Enthusiasts Forums - View Profile: fordman75
His build shows a whole lot that must be done.


Part swapping seems more complicated and more work, but it's not really, least not with 4x4 parts, maybe the set-ups are different to switch over for AWD.

You mentioned it was on a 4x4 frame already, so does it have a 4x4 front axle and transfer case already? If it does, why not go 4x4 instead of AWD? I love AWD, we have an Audi that screams around corners because of it, but on an older truck I'm not sure if you will get any benefits from it over 4x4. It's a truck, not a car, handling isn't it's critical game. But with that being said, a proper AWD '54 just has a very cool factor to it, and that's hard to beat.

 

Everything before 2011 Explorer. The 2011 became in effect a crossover