JC Whitney has some stuff.
The spring over axles is the best approach. With wider old bronco 9" axles. A body lift helps a little but makes it top heavier. The 2" shackle and torsion bar would be the first step. These vehicles have too much expensive sheet metal to do much rock crawling. Mine hates rocks but loves trees. Hits one every time it gets a chance.
Bob Shaw

87 Raizer, 4.3V6, Mod TH700R4,231CHD, detroit rear and LSD front, bouncy seats, 2" lift and 32x15 BFG MT tires.