You are at the right place, and I encourage you to read, read, and read some more. We were in the same situation as you a year ago, and after much research, and looking at different models, decided that on what we wanted, then the search was on. We liked the layout of the 25' Classic, with twin beds and the fold down tables. We felt it has the most room for the overall length and is finished out nice on the interior. Unfortunately, this seems to be a popular model and while finding one is hard enough, most seem to sell very quickly. Our longest trip to date has been two weeks, and to say that we are elated with it would be an understatement, and all we do is look forward to our next trip. Good luck in your search, hope you find one close, and don't forget that Airstream folks love to help.
Rod & Jane