"keeping for many many years"...are you sure?
You're changing now because the kids are older and need separate beds (we did the same). As they become teenagers they may want to camp less (aka be home with friends..bring friends camping is a 'something little kids do' so our 13 year old has decided this year).
once they're 16+ they'll prolly camp less. this is based on my family, friends, etc. YMMV and it would be interesting to see what the community says (i'll go start a thread on that!).
So if this 'pattern' is one, then you're 7 year old will 'quit' camping in 6-7 years and you'll be ready for a different MH.
Jill & Chris, Wills (14) Evie (11) & Toby our collie (5)
2011 Grey Wolf 28BH
2013 Chevy K1500 Crew w/ Reese StraitLine Dual Cam
Nights camped 2011: 11 2012: 18 2013: 12 2014: 12 2015: 13 2016: 3