Gear selection depends on speed and if you plan on using the tow/haul feature which greatly increases the exhaust braking.
If you plan on using the tow/haul, select the 3.73 or possibly even the 3.42 as the 4.10 will have your rpm too high.
If you don't plan on using tow/haul, the 4.10s are better because it will allow the 6th gear to be used more.
My father ordered his 2016 with 3.73 and when he hauls a 5k TC, he wishes he had the 4.10s so he could run 6th more often. However, he often switches between tow/haul on/off depending on interstate vs stop/go or where he wants the exhaust brake to really work. When he pulls his 16k# FW, the 3.73s are almost perfect because he runs 5th in tow/haul for the exhaust brake.
In regards to the trim level, look at the SLT. Gives you the chrome, sliding rear window, power seats, upgraded seats and a couple power points yet keeps the smaller radio. Only negative (IMO) is the updgrade from manual to electronic shift transfer case. The SLT is worth the extra $2k over the tradesman without getting into a lot of fancy stuff like the 8.4, auto climate control (which I hate).
Don't complain about the mmpg. Of course, I'm averaging 12.4 with a 2015 6.4 hemi and 3.73. You aren't going to do much better with the diesels today. If you want better mpg, going with a pre 2007.5 5.9 with the added benefit of going.
