Thomas, I'll put my two cents worth here. If you only plan on being her a few years, how about a recycled rental unit. They may have high mileage but most have been well maintained and look good. Ask IAMICHABOD, he posted about his experience on 05/07/12. I have talked to him a couple of times and he is very helpful.
As far as the 10 year rule. The only places we have found that are very strict about the rule are in Oregon. Both on the coast and both are RESORTS where you buy the right to park on their property and they only allow COACHES. I'm sure there are others all over the country but I've never been asked.
At the Oasis in Las Vegas, we were asked if we had any broken or cracked windows. Seemed weird but in retrospect, I can think of a few reasons.
Don't know zippedy do dah about Eugene but there are quite a few places from Westlake north to Lincoln City that have year round full time residents. Some are very nice and some are seedy. To paraphrase a friend, "Living at the beach is a lot like sex, When it's good it's very, very good, and when it's bad, it's still pretty good". I'll bet near Bend are a few and down as far as Roseberg off I-5.