Truck for arctic fox 1140

Last year I had lance 1172 truck camper appx 5,000lbs on a 16 ram 3500 drw with 385hp 900lb ft and 3.73 gears living full time in Los Angeles. My experience has been that I could have used more oomph so next year when I get a new camper I'm going f450 with 4.30 gears on 19.5" wheels so it's similar to a f350 with 4.10 on 17" wheels. The main reason I'm getting 450 vs 350 is because of the wide track front axle that turns more sharply which would be very beneficial for boondocking in tight places and negotiating city. In tow haul mode I would be hitting approximately 65mph when shifting into 6th gear. For most driving I wasn't over 65 anyway so lower gearing I think would be similar mpg wise. Also, get a bed liner. Even with a very heavy duty bed mat I had craters in the bed from the camper weight. Hope this helps.