smackaduck wrote: maybe dropping down to 4:10 gears.
4:10 gears? if you want to change gears for better fuel economy you need to go with something like a 3:08 or 3:42 ratio. depending on the year your PW is a full time 4X4 and probably is someware around a 3:42 gear ratio. A lockout kit will help a bit if you have not already converted it. Remember the higher the number the lower the gear ratio which gives more power but less fuel economy.
Also if I remember correctly the power wagons did not have an overdrive trans. Easy to retro-fit a later model chrysler OD trans into your wagon with the kits available now that include the wire harness and computer and the prices are not bad, Would sure beat a $450 car payment and that HIGH insurance.