If the sum total of your camping is a few nights at a Flying J - I'd just buy a small, used "C". But you're probably going to get clobbered on depreciation on the sale of your big C. Since you already have a NICE one, maybe you should stay in a few nice parks, and see if your wife might enjoy the RV experience??
Personally, I would NOT want to stay in a Flying J in my pop-up truck camper. I'd be smelling diesel exhaust all night and hearing all too clearly the general commotion that goes on in a truck stop. And I wouldn't have a genny.... the beauty of a TC is the ability to go where other RVs can't go.