Your experience is very similar to mine. I had 4 truck campers in the early years and when I retired the move to a 5th wheel was part of the plan. I'm now on my 3rd 5th wheel. Yes, I'm getting old !!
The first two 5th wheels were used. We started with a 24 Low Profile Forest River and soon traded for a mid profile 32 CrossRoads Cruiser. Like all RV's you have to look hard for any sign of leaks around seams and windows. Delamination is a cruel result with no repair possible. You're going to have trouble finding a two bathroom model under the 33 ft range. Rear bunk room models are very nice if you have guests, they can be found easily if you look online. RVtrader.com is a good place to look. Be prepared to drive a few miles to get exactly what you want!
Our current and last 5th wheel is a Grand Design Reflection 31' with 3 slides and a rear living area. The kitchen is in the center of the trailer. We soon discoverd years ago this is a good layout for us. Most campsites have a better view out of the back than on each side due to those other folks camped beside you. Our first 5th wheel had a rear kitchen and immediately we discovered that small window over the sink did not allow much of a view. Large windows in the back afford much better possibilities at most campsites. This will be a take away for you with a rear bunk model.
This last 5th wheel we bought new and there were issues, all covered by warranty. It seems there is nearly no quality control at factories and they rely on the dealer to correct issues. I fixed many issues myself but it did require 3 trips to the dealer (30 miles away) and a waiting period to get things resolved. This is a good thing about buying used, someone else has gone thru the shake down and all issues should be resolved. Never forget the delamination issues caused by leaks. This you can see and if you do then run away!!
The main difference you will notice in moving into a 5th wheel is the fact that trips will now require more planing!!! Not all campgrounds, especially state and national parks can accommodate large RV's due to length and overhead trees. Getting in a out of fuel stops can be challenging because pumps now require you to pull forward toward the building. This is so the attendant can observe activity at the pumps without a blocked view of the first row. However people parking in front of the building does not allow you to swing wide enough to get out. Also beware the back of a large 5th wheel will pivot in a tight turn and some accidents have occurred where the back of the 5th wheel hits a gas pump!!
With diesel you can use truck stops which is much better for maneuverability.
My plan is to keep this 2017 5th wheel a few more years then move back to a truck camper!! I have never been turned away from a crowded RV park when using a truck camper. They will find somewhere to put you normally! We once parked along side the park office and plugged into the outlet on the building. Big rodeo in Cody Wyoming and there were no more sites anywhere. We were heading home and were only needing an overnite. They made room for my truck camper!
So to sum it up, nothing is perfect. You have trade offs you must deal with. Truck camper is a very easy unit to travel in. If you can park the truck then there is no problem. With a large 5th wheel in tow you have to plan ahead and beware of boxing yourself in or finding a parking lot big enough to park sideways over several slots. WalMarts and such will normally have room for you to park way out from the building for a shopping trip, some even allow overnight stays. 5th Wheels are very stable to pull even with some crosswind. Good choice over a bumper pull RV for that reason.
Good luck in your hunt