I have an 18 ft with a corner bed - the head is against the drivers side wall and the the bottom "end" is open to walk around the lower left corner and that is a huge plus. You can kind of see this in my signature.
(The lower right corner is the pass through for the storage compartment, but that makes a nice shelf for the TV.) I put a wooden two step stool at the foot of the bed, and it is a breeze now for me to get in and out even with a bad knee and sleep next to the front wall. The lower step of the step stool is all I need and since it is out from the bed it is great. If my description makes no sense, it is similar to this:
https://www.walmart.com/ip/Home-Craf...olors/54695615
I put a fleece body pillow next to the wall and I am actually more comfortable than in my bed at home because I can sleep right against that body pillow with no worries about falling out of bed. That makes it easier on my bad back.
Mine is 8ft wide and as has been said, that extra foot is huge. It enables us to have a nice aisle from the bed to the rear bathroom and makes our decision to have no slides a good option for us.
The floor to ceiling space is well over 6' - at 5' I need to use that bed step stool to use the microwave over the stove or to get items out from the cabinet over the sink. But, that is a plus for my 6' tall husband.
My daughter talked me into bunks for grandkiddies, but they make fantastic shelves for camp chairs, musical instruments, duffel bags, and various "necessities" that I don't want to put in our half ton truck bed, but do not fit in the overhead bins.
The bathroom is big enough to turn around in and there is a tub/shower. I love the wardrobe in the bathroom at the back wall.
It is more than enough room for the two of us and a small dog.