We have the 3170DS, I am 5'10" and my feet hang off the end of the bed a little bit. You would think, How is that possible...the bed is 74" and I am 70". Let's be realistic, Who sleeps with thier head touching the wall?
Anyway, when the slideouts are pushed out we solved this by pulling the mattress off the bed about 6inches and filling the gap between the mattress and wall with a large rolled up comforter. The pillows rest on top of this gap and the extra length gives us plenty of leg room. Now our 74" bed is 80"s.... Best of Luck on your RV choice..
2011 SunSeeker 3170DS