A toad is a vehicle that many tow behind their motorhome. As for milage, it all depends on many factors, driving habits, speed, type of roadway ( interstate or back roads ), weight of your rig and how much your carrying, ect, ect. Many keep their speed to 50-55, others maintain the speed limit, like 65 -70 on interstates. The tune of your engine, air pressure in your tires, on and on and on. There probably aren't two people on this forum that get the same milage, even if their driving the same rig.
I have a 30 foot class c and tow a Subaru Crosstrek. On my recent trip I figure I got 8-9 mpg. Didn't keep track and don't care. We were having too much fun to worry about it.
Grumpy