Hi Rob,
Recently found myself in the same situation as you except my kids are 4 and 1. I ended up finding a near mint condition 2005 Starcraft 18SB for $7k. The big thing for me was finding a camper with NO leaks and this camper is completely leak free. Everything else looks like it was barely used by the previous owners.
I looked a few older Rockwood Roos, but both of them had leaked in the bunk ends which left them soft. One of the Roos was so soft that the previous owner was putting down a sheet of plywood to support the mattress!! I ran really fast from that used camper.
You should be able to find several that fit your budget and tow vehicle on Craigslist. You just need to take your time and look for one that has no leaks and has been well maintained. They ARE out there!
Dont be afraid to look and press on everything to see if its soft from water penetration. Take an especially good look at the roof and make sure that there are no cracks in the caulking or tears in the rubber. Signs that it has had roofing caulking reapplied is a good thing! It means the previous owner kept reapplying as needed to keep the water OUT!
Jon