The choice is between having a tow vehicle pulling a 5th wheel trailer and a Class A motorhome pulling a small vehicle. When you stay at a campground you will want to have either the tow vehicle or the towed/toad vehicle to get around.
The 5th wheel trailer will provide the most space though it will be on two levels. It will also have a greater load capacity for water and gear as the axles do not have to support an engine and heavy coach. The 5th wheel trailer is also going to be better insulated and easier to heat or cool year round.
Best to go to campgrounds and talk to as many people as you can find using each type and see how they use them, how storage is accomplished, what they like and dislike, what they had before it and what they plan to have next.