Ok, so a Toyota mini truck frame on Dana 60's with 4 link front and rear, using either coilovers or air shocks, a 350 engine, probably an automatic trans and a 203/205 doubler.
You must have a decent budget, I'd bet that's easily a $20k build. What about tube work, are you going to do it yourself or have it done? Have you thought about a F-Toy chassis?
If you can afford the coilovers F & R, go for it. They take some tuning to get them to work, but once tuned in they'll work well.
If you're on more of a budget you could run leafs up front, then 4 link the rear with air shocks.
There's a few companies out there that make a weld on kit which will let you bolt a GM Dana 60 under the front of a Toyota using Toyota springs-
http://www.sky-manufacturing.com/new/detaproduct.php?id=184
Get a quality pair of springs like All-Pro or Marlins and they'll work well enough for rockcrawling.