Budget crawler...
3/4 ton diff's, pretty cheap to get (under $400 usually) and have decent gears almost guaranteed. Most have 4.10's. Chuck a Detroit in the rear (~$400) and leave the front open.
4" lift, but not a kit. TC EZ rides up front, shackle flip in rear. The flip can be free if you're handy with a grinder. The EZ rides will ride and flex good, but not be so crazy as to make crossover steering a must. Relocate the rear shocks, run the cheap Gabriel 12.5" travel shocks.
A set of 15x10 rockcrawler rims, ~4" backspace, and some 35x12.5" MT's.
Keep the Q-jet whatever you do.
Bumpers of your choice, just keep approach and departure angles in mind when designing/building/or buying them.
Box tube "weld on" rock sliders.
Part time kit for the 203.
Do a little front fender trimming and have fun with it.
Total might be $2200-$2500 and it'd be a pretty capable trail rig.
Rene