The 2nd t-case will only help you out off-road, not on road. Unless you swap in a 4.3 or Supra engine, all of the mod's you are considering wont have the same effect/increase in power as regearing will. Also any HP you do gain wont be fully realized because of the gearing issue, and it is very unlikely that the cam and head would give you the garaunteed 10% increase in performance that the 4.56's will. Also, if you figure you will be towing the tent trailer on a usual basis, or if you live in the mountains/travel there often, you might even consider getting 4.87's over the 4.56's. Both are oem gear sets, and should run you about $150-250/diff. The 4.87's would allow you to eventually run 33's with the lift you have and still retain the stock gear ratio.