We went with an Alpenlite 29RK (29 foot rear kitchen). But when we measured the 5th wheel from bumper to tongue it is 31 feet. Then, we add our bike racks on the back and it's longer still. And we also put kayaks on top of our truck that stick out the front.
So, I love our Alpenlite because it was one of the most efficient (in terms of space) and my husband likes it because it is sturdy. We get into a good share of places, but there are places we can't get into because even at that size we are too big.
When we are camped, we spent very little time inside our rig. We live outside in the campsite. And when we started full-timing, we had two BIG dogs to boot. We were fine.
After a bit of full-timing, we took the plunge and decided to go to Mexico and then I was really glad we had the rig we did - sturdy, but not too long.
We didn't know for sure where all we wanted to go when we started - but if you know your general lifestyle and buy a rig that fits that, then when you add new places to go to, you should be fine.
Everyone has different opinions on this topic, but I say it boils down to how you live. If you love being outside and in more rustic, scenic areas, then you will be glad you have smaller. If you like to look out your window at the scenery when you are watching TV on your big screen and need "moving around" space to be in the inside, then you need bigger.
