The other consideration is the mpg when fully loaded. A smaller high revving gas engine now o days is geared to get the best mpg with 1 driver with a light right foot and no load at all driving with the wind on the flat. One bright spot here is the newer close ratio 8 speed automatic transmissions that keep your revvs at the optimal point: high, depending on the make. The minute you load up your 2900 pounds the mpg drops precipitously. In the past my favorite gas engine for a 3000 pound TC was the V-10: Ford or Dodge. Yes, poor mpg even with no load, but does not drop as far as a small gasser with the same big load. I’m afraid there is no free ride with a small gas engine and a big load.
Oh, and you never, ever hear someone say, “I have too much truck for my camper”.
This is a common paradigm shift for noobies.
2020 Ford F-350 XLT FX4 4WD SRW SB SC 7.3L Godzilla Gas TorqShift 10R140 397 amps dual Alt dual batts Frnt Dana 60; Rr Dana M275 E-locker 4.30's 4580/4320/4066# payload 7243# curb wt. 11,300# GVWR 5-er prepped. 2020 Northstar Laredo SC, 12v compressor fridge, cassette, 320w Solar sub zero insulation.