First things first. Have you owned a motor home before? Have you had a camping trailer? Do you KNOW you will like this method of travel and lodging? (notice from my handle I don't call it camping anymore).
If you answered no to any of these questions, then the very first thing you want to do is rent. Try it out. You may find that although your DW says she would like to travel in a motor home, she may be saying that to make you happy and would rather be calling room service in a Hilton than making your breakfast. I have known people who have bought a 650K MH that now just sits because what they thought would be cool, just wasn't that much fun for them. My wife and I just returned from a 2 1/2 month trip totally across the country and we can't wait to go again.
If you've never owned a motor home, this is the best advice you will ever get, rent first. This will be money well spent and can save you more than you realize. Try out the lifestyle. See how you like to drive different models and classes. See what you like or hate in a floor plan. Make sure the pain at the pump is not unbearable to YOU.
Of course, you may be seasoned 'old hands' in which case that's a big 'never mind'. Then just do your research and be tough at the dealer, you'll be fine if you're happy in the end.
