They're cool.
I'm seeing more and more of them.
On a 4x4 you can penetrate areas that are a no-go for conventional rigs.
I have an '09 Taco that has a Snug Top with the reinforced top.
It would be perfect for a RTT.
Presently I rig rig a heavy duty 9x12 tarp off the back of the Snug with Eureka 5'-9' tarp poles.
These are some of the best adjustable tarp poles available and an absolute must-have to make the system work.
Hard to find (Austin Kayak).
The reason I mention that is that you really need a covered cooking/sitting area as well as the overhead sleeping area.
The RTT's with the "ground floor" option look nice.
Also be sure to
COMPLETELY dry out your tent system before long term storage for the longest service life.
