Welcome to the forum and congrats on your almost new Ace. I would guess you use a gps and if so, you can find a lot of useful files at the Point Of Interest Factory here;
POI Factory | new & interesting places for your GPS
including bridge clearances to help with avoidance.
I guess a safe speed is what you are comfortable with within speed limits. We usually stay around 58-60 mph mostly for fuel cost which is around 1950 rpms. We normally do 200-350 miles a day sometimes more or less depending on destination, sights etc. We try to stay in PPA campgrounds, national and state parks and some boondocking for convenience and to save a few bucks
RV safe driving courses are sometimes offered by the dealers. We took a course offered by the dealer we bought from a few years ago and picked up some good tips. You can see some of those here;