Valk, both trucks have the shorter (5.5?) beds, which is plenty.
The 99 with the V6 really does well on gas, although to be honest, I have never checked it! A tank, in-season, usually lasts me 1.5-2 weeks. All my accounts are so close, is why it only has 84g in 13 years!
The 2011, from what I can tell, is gonna be pretty easy on the gas intake-the 3.7 V6 is super smooth and quiet. and for my situation, has all the power I need. (My trailer holds 3 48" walkbehinds.)