From another forum, years ago, I learned to tie a piece of cord to the access cover and then to something else. No way to loose it or forget it after filling propane.
Thanks! I even found a color that matches well. Since I had to buy a 4' piece, I have three more if I need them.Lowes. It is just a piece of wall foot board (Plastic) cut to size. I don't expect the new Roadtrek to sell it but the old Roadtrek sold it for $50. Ace probably has it, too, for less than $2.