We full-timed for 8 years in our Newmar Dutch Star with a Spartan. No issues. If you're choosing one because of basement space, any diesel over 40' is going to have plenty. We had room to spare. Besides, you're going to be hauling a garage around.
Which brings up a point....a 45' with a cargo trailer to hold a car means you'll be limited as to the types of parks you can go. We had no problems in public parks, national parks, national forests, Corp of Engineers, county and city parks with our 40' towing the Jeep. Think it out carefully.
Definitely get a side radiator!
