Picking a camper is all about figuring out which compromises you want to make. It's hard not to want everything checked off your list of must-haves when you are making such a big investment, but the reality is that you will have to make compromises. We have a FWC Hawk with the regular queen size mattress. We are both right around 6 feet tall. You would not be able to sit all the way upright in the bed area, but we have spent many cold nights before bed in the camper listening/reading and my wife has no problem with hanging out on the bed partially upright. We sleep east/west, but the only time one of us has to crawl over the other is if I go to bed first. I sleep on the rear side of the bed because I get up really early. When I wake up, I just roll my legs out of bed and sit on the edge so I can turn a light on and get my glasses, then I step down. Because of back issues, "rolling" out of bed is important to me and I would not want to sleep north/south. When I am sitting on the edge, I am not fully upright, but it is pretty close. Neither one of us has to get up in the middle of the night. The crawling over thing is really only a minor inconvenience. Unless you have severe mobility issues, I think a king size bed option in a FWC would be fine for you so you could sleep north/south.
You should definitely try to see any camper you are interested in at a showroom before buying; it will help you figure out which of your must-haves are actually just want-to-haves. It is also important try a pop up before you buy so you can see what the ergonomics of entering/exiting and popping the top are. I had a herniated disc in my lower back and my wife had major shoulder and elbow surgery. We are both fully healed but necessarily cautious, and the pop up is fine for us, but I could see someone with moderate to serious issues not wanting a manual pop up. Many people use speaker lifts as a jack to pop their lid if they have limitations. As we get older, I could see us maybe switching to a different style of RV, but the FWC is perfect for who we are now.
As for the weight, our Hawk is fully-loaded with the biggest fridge, furnace, water heater, etc. It is the side dinette configuration. Dry weight is just under 1500 pounds. Tank and water heater hold 215 pounds of water, and the camper also holds 20 pounds of propane. That would still leave 250 pounds of room in the camper for gear/beer before you touch the camper weight rating for your truck. I have read a few discussions on camper weight ratings before and it seems like the general consensus of speculation for the reason is the vehicle manufacturer being concerned about the wide variables for weight distributions across the many different camper options, but who knows.