Here's a great way to quickly and easily make the RV-queen mattress 4" longer for those of us 6' and over.
Have a bolster made with one dimension being the thickness of your mattress and the other dimension 4" (like 4" x 10" or so, depending on your mattress thickness).
Use the bolster to lean against, with pillows, when sitting up in bed reading or watching TV.
Then, when you're ready to go to sleep, pull the mattress away from the wall 4", drop the bolster down at the head of the mattress... now your short-queen is 4" longer, made so under where your pillow lays! Instantly, your bed/mattress is 4" longer!
When you wake up, pull the bolster up and out, slide the mattress back up at the head, and place the bolster for use as a backrest again.
I didn't originate this idea, but just passing along to anyone who may appreciate it!