I'll be towing a subcompact 4-door sedan using a Uhaul/Ryder/Penske 15-foot truck.

I was curious to know what the recommended speed for this combo is. I would take either the two-wheel dolly or the 4-wheel car carrier (My car is front wheel drive), any difference? (stability or speed or safety-wise)

Also, I'm sure driving a truck/moving van is more tedious and taxing than driving a car, so what do people recommend as a safe and comfortable daily number of hours or miles to drive, before I stop at a motel for the night?
Is there anything people on this board might want to suggest (additional precautions driving a truck and towing a car cross-country)?

Also, since I'll be renting a larger (15-foot)truck than I need (no towing permitted with 10-foot trucks), its going to be lightly loaded. Anyone have any idea what kind of gas mileage I can expect, if I stick to recommended speeds and speed limits?

My route is over 2000 miles, so I feel this is important info to help me decide how to plan my trip!

I'll also be posting a message (in the appropriate forum) asking if someone wants to share gas/motel/van expenses for a move, from the Mountain West (Salt Lake UT or Boulder CO)
to DC-Metro area. I could go via the NY/NJ area if needed, too!

Thanks in Advance!