Interesting reading the answers to your post with quite a number of them pinging the 25' range (not always clear if they mean box length or total length though).
I think it really depends:
- what you expect your "camping experience" to be like (i.e.; are you happy sitting at the dinette all the time or do you "want" a separate seating area).
- how many people (don't forget visitors and pets) and how much "personal space" (i.e.; privacy) you want.
- where you want to go (boondocking, public CG's, private CG's)
- the season and how much time you intend to spend inside vs. outside.
- how flexible with travel plans you want to be.
- the floor plan of the trailer (one big open space vs. interior walls).
- what you are lucky enough to find when shopping.
- many other variables that I can't think of right now.
Our 22' box (with one slide) trailer has no room dividers (except the bathroom of course). And we find that about half the time it is either too big or too small with the the other half of the time being just right (sort of like the three bears story). Of course, this may change as we get older and/or we stop preferring to boondock, but for now, this length works well for us (keep in mind that we are backpackers and rafters so are comfortable living with less).
It is interesting to see that our trailer length jives about right with my earlier observation on the ~25' length being the most often mentioned in the responses to your post.
My guess though is that, whatever length you eventually do get, you will conclude that it is perfect.....for you. Happy shopping.
