We have a RTT on a Comanche. It's good for getting way off the beaten path, but not so big on the creature comforts your SO will want if she's just hanging out.
We have an older Haulmark popup truck camper that is our go-to camping unit. We have many vehicles, so the truck camper stays on the truck most of the summer, unless I need to pull something really heavy.
If you want real 4 season capability, I'd suggest a full hard shell camper, not a pop top. We've spent nights in it where the temp got down around zero, or just below and it's doable, but with the heat set at 55, the furnace runs as much as it's off. At temps in the 20's, it's only a little better. It doesn't really make sense till the temp is above about 30F. And with the soft sides losing heat fairly quickly, the person who sleeps farthest forward (E/W layout) is usually a bit colder, while the person closer to the heater is warm.
The pop top does also have an additional disadvantage if you're coming out west... We've been ushered out of a few campgrounds in the northern rockies where bears are frequent. Signs say NO SOFT SIDE CAMPERS and that includes truck campers. Of course, we went just a few miles up the road to FS land and dry camped, which is our normal preference anyway.
Our Haulmark hangs about 2" over the end of the tailgate, so there's no climbing over anything to get in. I would recommend getting a camper that mimics this layout... Don't buy one that fits inside the bed, or doesn't fully overhang the tailgate unless you have a full 8' box. FWIW, our haulmark is an 8.5' camper and my Sierra has a 6.5' box. This is the perfect combo IMO. I can't imagine life cramped in a 6.5' camper... The extra storage and living space is what makes it comfortable, IMO.
Also, we bought a Phoenix Sasquatch last year to fix up and replace the Haulmark. Strangely, it's a couple inches wider, but feels a LOT smaller than the Haulmark. The seating area is smaller, and it doesn't have nearly as much storage because the floor is narrower, and the bulges behind the wheel wells are also narrower. I need to spend some time with a tape measure to figure out what my options are to make it bigger... It's in need of a remodel anyway, so it may get a more extensive one.
While neither of our campers have toilets or showers inside, I do recommend at least an outside shower and water heater. If your wife needs a toilet, you get an inside shower with it on most setups. The hard side will again have a much nicer shower/toilet setup.
Good luck finding something that works for you!!!