84 Toyota Pickup to 4pickup Build Thread

Yes, I already know that there is another thread I put on here with almost the same name, but this one is going in a different direction. Since I now have a job, I am able to afford more of what I want.
Some of the things I want to do is:
1. Put a 4runner shell and seat in the back, since I have more than one friend, a little more room would be nice.
2.Put an adapter kit on to adapt my weber on the pickup.
3.Get a rebuild kit for the old 22r
4.Replace the front axle. (The slip joint is toast)
5. Get electric windows and mirrors
All of these are pretty much in order of importance.

So on the 4runner shell:
I went to the local savage yard a few weeks back, and I saw a red 4runner shell, I didn't have my truck then and I was wondering if it would work on my pickup. So I did some research and found out that the 1st gen 4runners are 2nd gen pickups with slight modification to make it an SUV (When I say slight, all they really did is made a unibody out of the cab and bed, cut the back of the cab, raised the roof a few inches, put some carpet in the back, put a roll bar in, put a heavy ass rear window/door on the back, threw a seat in the back with some seatbelts, and put a fiberglass shell on ). Toyota overlooked building the suspension to be able to support a full load, resulting in sagging when they are fully loaded.

I went back yesterday and asked about it, they actually didn't know that they even had one back there, and asked me to name a price, and I said $50, and they almost craped their pants, it was pretty funny, I think I should have said $25. So on my b-day (Feb/17th) I am going to go down and pick it up. I thought about it and what I wanted to do is:

Bolt the shell down, and push it up against the cab to make a watertight seal.
Build a back window with plexiglass, and build a metal frame for it.
Make it so it is sealed on the bed, and air wont rush through
Get a seat and some carpet.

Here is my number one concern FRAME FLEX!! I am worried that if I bolt the shell down, and have it tight against the cab, when I go over anything that flexes the frame it is going to put to much stress on the fiber-glass and eventually break it, So I got a few Ideas.
Put large washers on the bolts that go to the cab, and elongate the holes, so it can move back and fouth. (actually after looking I may just have to go with the 2nd option, the shell is both a little to tall and wide on the front)
Or use that rubber stuff that fits around the back window to make a seal. (But I think it is spendy)
So what do you think??? I think I type way too much.;)

Look at how toyota did it and copy it - take a sawsall and cut the mounts off the donor truck where the shell mates to the cab - its not like they are going to care, they are just crushing it anyways. If the tailgate is there, get it too. For the cab/bed gap - do the old skool walk through where they tie the two parts together with metal - it doesn't have to be unibody. You could even build a wooden frame between the two for extra support and strength. Thats what shop classes are for - what a project!

The only issue is that the truck I have now is still being paid on (Only $600 more until it is paid off) and they just had the shell laying out in their field, the 4runner is nowhere to be seen. The only problem I have with the tailgate is it weighs a lot and is much thicker think of a 40's car, and how thick their doors are that's about how thick these are. I looked on yodatech and most of the threads there are going the other way around, from a 4runner to a pickup. I also still want it to be re moveable and not have any permanent modifications done to the truck (Some holes are fine, anything much more than that I don't want to do.