I agree - grab the tent and use it. Right price, lots of room, you don't have to carry it.

As far as its size: no one (at least, no non-backpacker in the public campground) thinks the guy with the two block long RV with the crank-out side room and the roll down awning doesn't get it, so you've got nothing to worry about. If, in some remote possibility, someone does make a comment, explain it to them the same way you just explained it us - if you feel compelled to respond at all.

Sounds like you're taking a good, common sense approach to getting into backpacking. Once you find you like camping, try to buy backpacking gear (stove, mattress, sleeping bag, and such) instead of car camping versions - backpacking gear works just dandy for car camping, but not vice versa.

Good luck! (And enjoy all that room. If you run into some backpacker's, invite them into the pleasure palace for some cards - and pick their brains about getting started in backpacking.)