Before you start looking any further, check the towing specifications for your Outback. Some have fairly low towing limits and many have an unusually low tongue limit.
There is a listing of "Real World Weights" of FGRV's in the general chat section that will give you an idea of what can and that shouldn't be towed with your Outback.
Also keep in mind that refurbishing can get very time consuming as well as expensive. Buy the best you can afford up front and you will usually save money and time.
And Last: Follow the for sale
listings here as well as at "fiberglass-rv-4sale.com", but ask lots of questions before you buy, there are a lot of pitfalls in FGRV's to look out for out there.