What I have found is that virtually all "Buyer's" are looking for the Top of the line Coach, new or used with all of the extras, upgrades and add ons. But they only want to pay for a bottom of the line coach with no extras, upgrades or add ons at a deep discounted cost. But from a sellers standpoint, unless you are desperate to sell wait for that "Buyer" that will show up and say that is exactly what I want and I see the value added in your Coach. Might be a long wait but they are out there.
So make the upgrades that please you but realize that increasing resale value is in the eye of that Buyer that really wants your coach.
2003 Forest River Cardinal Platinum 37' 5th Wheel
1976 31' Airstream