You need to visit a few RV dealers and just look at what they have. It would also help if you rented one similar to what you think will work for you.
And since this is your first RV, I'd suggest a gently used one. Plenty of nice used ones out ther, but you need to remember "Buyer Beware". Have an independent RV tech check the proposed rig over and also have a shop check the engine and drive line. This may cost you a couple of hundred dollars, but could save you much more by avoiding one with problems.
When you get ready to make the deal, make sure that the person selling the RV (dealer or individual) writes everything they promised into the contract...not in the contract, things get "forgotten". You should not pay for a separate make ready or demo fee as this is part of them doing business.
When you get ready for delivery, make sure the RV is 100% before you sign the papers or give them any more money. Let them know,you will not accept delivery or pay for it until it is 100% complete and finished.
Now go have fun shopping.
Amateur Radio Operator (KE5DFR)|Full-Time! - 2012 6.7L Ford Crew Cab Dually -2013 HitchHiker Champagne 38RLRSB - Travel with one Standard Schnauzer and one small Timneh African Gray Parrot