A few other things come to mind. What is your RV experience level. If not much, I would suggest renting one for a week or so to see how much you really enjoy it. That would also give you an idea as to floor plan you like or don't like without committing to a large expense or floor plan you don't like.
You mentioned used, so decide what your price range is. Newer, be more fussy about details, colors, floor plans, brand, model, etc. Older lower priced be less concerned about brand or model, more concerned about actual condition of RV. How you intend to use it also means a great deal. Parking in one place for long periods of time is one thing. If this is your plan larger is better. Moving every few days smaller might be better. Is the wife going to help drive? Also an issue.
Now is an excellent time to buy class A or class C RV's. Used ones can be had at good prices now due to lower fuel economy than other models, and if you will be financing, rates are at all time lows right now.
Look at the used RV sites for more ideas pplmotorhomes.com. rvtrader.com, rvt.com for more ideas. Visit some dealers and rv shows for more ideas, but I would again recommend renting to get a better idea of what might suit you.
George 20 yr USAF & Lesley