I looked for over a year before I ended up buying new. The problem I kept running into was that really clean used units were priced so close to the new price it did not make sense. The NADA prices are really inflated and everyone wants to price by their retail list. My new unit is now 1 year old and NADA says its worth more than what I paid for it. That and many people I went to see were so upside down on their loan they could not move on price.
Stay vigilant and go see everything you can on craigslist or the RV lists. You will soon find you become educated on wording to watch for and be ready when the right one comes along because if its really nice and a good price it wont be there in a few days when you make up your mind.