This thread has meandered in many interesting directions. But if we go back to the original question regarding an affordable 4x4 for mild overlanding and camping, there are a few major considerations:
1) Initial cost vs resale.
2) Cost (and hassle) of maintenance and repairs.
3) Cost of fuel.
4) Cost of insurance and registration.
1 and 4 favor used vehicles most of the time. But if we stick with new trucks, the best values are usually found on "tradesman" models with V6 NA gas engines. Plus the V6 will return an extra 1-2 mpg. Look for last years model that has been sitting on a dealer lot too long. Do nationwide searches. Flying there and driving home isn't a bad idea if it's the right truck for the right price.
People seem to focus on MPG too much IMO, and ignore depreciation. Depreciation may work against that V6 (versus the same truck with a more powerful engine), so make sure the deal is quite good to start with. A $50k truck will depreciate more than a $25k model. 10 years and 100k miles later the first might drop $25k in value while the other drops only $10k, a $15k difference in cost. People buying old trucks are more concerned about utility than bling. Different makes will also tend to depreciate differently. When I was looking, a 10 year old 100k mile Tundra was worth about $5k more than a comparable F150 (book value). I didn't look at Ram, but they were probably worse.
How much is MPG worth? In 100k miles ($2.50/gal) the difference between 16 and 18mpg is $1,736. Pretty small in the grand scheme of things. Nice if you don't have to pay other "costs" to get it, however.
a bit when people get rid of a paid-for gas hog in order to buy a "more fuel efficient" vehicle that they have to make payments on. 
