I think a Roo 19 (new) would be a perfect first camper, if they have a tow vehicle that can pull it, they would be set, I think if they got it new it would take the worry of some hidden problems out of the equation and just let them enjoy using the camper.
I almost bought a 19 last year, they have a lot in there and you can start from scratch taking good care of it. If they can swing it i would have them at least check out a new roo or shamrock 19.
They would be starting out with a LOT of nice comfort systems and it would be easy to unload if they didn't like it.