Everything in this world has a plus and minus, yin and yang.
I have a travel trailer and RTT. The wife definitely prefers the TT
.
I first bought one used years ago when they were a new concept as I was intrigued and got a deal that I could easily resell it for to be able to try it. The comfort with the right bedding can be almost like home and can be some great sleep. That can change a little with the weather but generally speaking still pretty fantastic.
The biggest issue I had as mentioned is it was mounted on my SUV and if you set up for the camp you are stuck there until you pack it all up. My second issue is the particular vehicle it was on was a vehicle that sees a lot of "black" trails at off road parks and trails and the size and weight that high up can definitely propose some stability and clearance issues in this environment.
I wound up winning another one at an event at "Windrock" and definitely considered cashing in on selling it but I had a lot of nice features my old one didn't and kept it with a different plan in mind and gave my old one to my Daughter as I knew they would use it and they do.
The plan was to find a trailer suitable to mount it on that almost any vehicle could tow and allow I to remain setup upon arrival (whichbisbalso nice to keep your camp site claimed, another issue with it mounted on the vehicle itself).
A luckily timed post on a local off road board and a reply from the man who built my rear bumper on my rig found me the perfect $700 trailer fabricated for this purpose that he offed to sell since he was building another military trailer up to replace this "project" of his.
This setup works well. It can be towed almost anywhere you want by almost any vehicle (my "wheelin" rig can't tow my TT). It can be left set up while you are out and about in the tow vehicle. It can also carry an ATV, a couple motorcycles or bikes and or extra storage depending on how you set it up for a particular trip. Has an awning option to hang out when the weather is bad. Allows almost no mileage drop when towing, and can be safely towed places the TT can't think about going unlocking the limitations of having a travel trailer.
Do I prefer the travel trailer in every other way? Yes.
We just used this setup to drive the entire Bue Ridge Parkway north to south and was definitely the right tool for the job IMO. Could I have towed the TT, I believe so. But it would of made many things more difficult if not more dangerous. I believe we would of had to plan for out of the way gas stops that was not an issue with the "overland" trailer. We would of had issues finding places to stop in a decent amount of the instant pull off locations that you intend to stop and get pictures, etc. There were also spots, including my favorite stop of the trip that without finding a place to unhook and leave the TT, we wound not of been able to get to.
So my take is it is probably trip dependent for sure but they do have some value but are still a bit of a pain to set up and take down. About the same as most tents I've used so don't let them sell you on that being the difference.
Edit: two more pros/cons:
With the RTT trailer when in bear country the food and cooking gear can be kept in the closed vehicle away from the tent if bear boxes aren't available.
Also the lack of stress and speed you can safely tow it vs a travel trailer. You almost forget it's there.