Reviving an old thread. If space isn't an issue the extra tall twin air mattresses with built in 110 pumps are super convenient, comfortable, and cheap (around $40). Whatever you do don't buy bigger than a twin, you feel every little movement the other person makes. If you want to sleep next to your significant other push two twins together to make a king. If multiple guys are staying in one trailer and storage space is limited a cot is nice for that little bit of storage underneath. That little bit of storage space can make a big difference. Eureka makes some nice camp cots with thin air mattresses you can get for on top of the cot.