Just open some windows/vents and freshen the air in the RV. That's a lot simpler than buying/hauling around a cooktop, and dragging all your cooking supplies outside. For the life of me I do not understand why people don't just use their RVs like a house.
But if you must cook outside, the Coleman 2-burner is a simple solution. The temperature control is not the best--it goes from OFF to LARGE FLAME with nothing in between. So you won't be able to simmer anything on it. It works OK for things like you mentioned.