Gesus Jimmy! 74+46=120 gal. @ say 15 mi/gal that is 15*120=1,800 miles. Where the FUCK are these no gas stations for over 1500 miles in this nation????
I suppose in theory the 3500 could get 15 mpg, if driving slowly and not towing anything.
But since its sole purpose in life is to tow, a minimum of about 8,000 and up to 25,000 lbs., it generally gets between 5 and 10 mpg. Sometimes into the 11s.
So not quite 1,500 miles - which would be great, since I hate having to stop. After all, there's a reason I added the 46 gallon auxiliary tank. Got spoiled by the Pete and its dual 135 gallon tanks, and the "new" one has dual 150s which will be nicer yet. About 1,600 miles is about all I can do in one sitting.