I'm a long-time Ford truck enthusiast, but have never paid much attention to vans before. Now I find myself seriously considering purchasing and/or building a 4x4 van for expedition camping. Mostly looking at 90's and 00's stuff, but a few 80's potentials are cropping up, too. Anyone know what the differences in the chassis and running gear are in these era's between the e150, e250, and e350? Specifically, expedition vehicles tend to end up on the heavy side, so I don't want to start with an e150 if there are real differences in the frame, etc.