RTT = Roof Top Tent 
It's doable to use just loadbars/crossbars along the bottom of the tent but if the tent doesn't have a solid floor then you'll want to have a full rack. I'm sure most tents have some form of finished floor but some might be thinner or less insulated that others. A full length rack is obviously going to be the most sturdy setup but the most costly as well.

It's doable to use just loadbars/crossbars along the bottom of the tent but if the tent doesn't have a solid floor then you'll want to have a full rack. I'm sure most tents have some form of finished floor but some might be thinner or less insulated that others. A full length rack is obviously going to be the most sturdy setup but the most costly as well.