Well as far as inexpensive, you could stay in Klamath Falls where there are a number of inexpensive hotels. Wife and I stayed at the Olympia Best Western and it was clean and acceptable. You could then drive up to the rim of Crater Lake and just ride the rim. The rim is not that bad as far as climbing is concerned and it's pretty easy ordinary as far as road conditions are concerned.
You may want to call and see if the roads are even open. I know they are closed for a lot of the Winter.
I'd recommend a nice low gearing if you or your wife aren't strong cyclists. I rode it with a compact double and didn't find it very difficult.
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