A simple solution for my husband and me is to sleep "head to foot". We each now have enough shoulder room whereas when we slept "head to head" we both felt cramped. Some people like sleeping bags when sleeping this way but we find that a traditional comforter works fine. We can both keep our toes covered and our heads peeking out. An untended, but welcome, benefit is that it's easier for me (I sleep close to the back wall) to climb over my husband's legs when I need to make a nighttime visit to the porta-pottie. Before you change trailers or make modifications, I suggest you try this method of sleeping.
The Gleeful Glamper
"Here we go again on another amazing adventure"