The first thing we upgraded, IMMEDIATELY in a Used RV - The Mattress

 If you bought new then you may be OK. but most RVs mattresses are not that comfortable. If you are buying a Used RV, you may want to replace the mattress right away. We replaced ours even before we finished delivery and inspection. It is one thing to be in a very nice rig and everything is beautiful and looks inviting, and then you get ready to go to bed and it is the most uncomfortable mattress and you wake up and have to go somewhere to get a new mattress or mattress topper. 

Make the choice, change it out and you will be thankful you did.