I have only used our TT for two trips and it was for the two of us, but I got this one with grandkids in mind for future camping - mostly for the reason in the second to last paragraph.
The top bunk weight limit on my Shasta is 250 lbs. Mine is an 18ft bunkhouse (single upper and lower bunks) with a dinette/bed combo that fits 2 more kids, and a queen bed that has two sides against walls, but the other side and bottom are open, so it is easy in and out. Sleeps six in the literature, but we can fit one or two more small grandkids in the queen bed with us - that is an advantage of one side next to a wall since kids don't fall out of bed.
Since your kids are all grown, I would say five comfortably - 2 in bunks, two in queen bed, and one in the dinette bed, which is only slightly wider than the bunk beds. But, as someone who usually shares a full size bed, the queen seems luxuriously wide to me at 60" and could easily hold three adults.
The bathroom has plenty of room to turn around in, but no sink. I prefer the extra space, and just wash hands at the tub faucet.
Ours has no slides (I consider it a hard sided tent with a bathroom and really nice amenities), so I don't know if that fits your needs, but other Shasta models do have slides. I prefer no slides as we can access everything when traveling and it is very quick to set up - once leveled, connect electric and water, hit the button for the hot water tank and we are pretty much good to go.
My 18ft is easily pulled with our half ton truck. The GVWR is 3,830 lbs. Specs and pic of the floor plan are in my profile.
Regarding tents and trailers: I used to have a 14ft Dutchmen - now made by Coleman - and it would suit your priority need for an indoor bathroom. It had a dinette that can be made into a bed for two. When we had it, I always took a Coleman Instant Tent and set it up at the back bumper of the TT to store camp chairs etc. We never had a problem in Ohio or West Virginia camping at state parks, COE, and the occasional private campground, but when we looked into Maryland, there were places where there could only be one dwelling per campsite - either a tent or a trailer, but not both. So, you may not always be able to put your kids in a tent. I felt it was a bit unfair since my 8ft tent and 14ft TT combo was still smaller than most RV's, and you had to look for the tent behind the trailer to see it, but their campgrounds, their rules.
Good luck in your search.
