One other unsolicited thing to keep track of is how old your tires are with a suggested 5 year life. But even when you get new tires check the date. Trailer tires don't always turn over quickly at some shops. Heard stores of "new" tires being a few years old.
We usually run right around 70mph, the truck and trailer combo seem to be good there. It also depends on traffic volume, etc. We carry 234 gallons of fuel, so that is one stop we usually do not have to worry about.