I also bought a travel trailer with a very poor mattress. I went to a local rv dealer and they told me about a local mattress maker they use. I had a very nice mattress made for $250. The exact size I needed. Search your local area for mattress makers.
I have a tracfone phone also. When I went to Canada a few years ago I didn't have cell service. When I came home I did some tracfone research and found they do provide international service. I have not needed it so I haven't sign up, don't know how it works. The number to call is tracfone at 1-800-706-3839.