[Brian R.]

Without major modification, there is little that you can do (that I am aware of). A solid front axle will help, but that falls under the "major change" category.

Larger tires will keep the suspension more stable since the tires won't fall into as many crevices or fall in as deeply. Bringing the tire pressure down when off-road should help.

A word of caution, many shops (tire/battery retailers) that do alignments are ill equipped to do alignments on your truck. They usually do not have the tools or knowledge to do the job of loosening the larger truck fittings and locknuts (tie rods, etc) and will really screw up the fasteners with the wrong tools, not knowing when there are reverse threads, etc. Take your truck to either a truck shop or Toyota to get an alignment. They will have the tools and the experience to keep your fasteners from being chewed up by bad tools and bad technique.