Your best option is to start touring a lot of dealerships. After a while you'll come to realize exactly what feels comfortable to you. Besides just walking through a lot of units, also take various sizes and brands for a test drive. If find one that feels good to you don't just walk through, take the time to sit down and let yourself imagine being in there 24/7. Just don't let the salesmen drive you nuts pressuring you to make a decision. You have the time to look around.
As to the size of rig for a full-timer...well that will depend on how you will travel and where, if you'll have guests onboard and any hobbies you wish to do while traveling. More space with lots of slides is nice but some people really love a smaller cozier coach that is easier to drive in certain parks. If you'll be doing boondocking or staying at natl. or state parks a lot you will may appreciate a smaller coach. I'd not consider any coach from about 32 feet to 36 feet too small to live in. Most fulltimers do go with a 40 foot coach.
In the price range you mentioned I'd guess you will need to look at coaches about 10 years old or older as mentioned by other posters. That is not a bad thing. Many older great quality units are out there but it will take careful examination to eliminate coaches with serious past, present or future issues. Even a well taken care of older coach will at some point in time need major renovations: appliances, tires, chassis/engine issues, flooring, furniture, body paint, plumbing repairs, etc. However redoing an older stable coach may be cheaper than buying newer/more expensive but it will take some time to redo everything. If you can do it yourself you will come out ok but if all work must be hired done...it can run into money. If at all possible find someone who is an expert to accompany you on your shopping trips. It is just to hard to tell if you can trust all dealership personnel to not show you a rig that has problems.
Try to enjoy the process and make it a fun project.
Suggest going to PPL in Houston for 2-3 days to climb through as many coaches as you have energy for. When you are completely confused, its time to write down your specific needs, length,floor plan,age of model,gas or diesel, tire replacement plan,etc. Your plan for use will determine many issues, ie short coach for National park/forests. Long coach for full timing in a few places. The upgrade to diesel causes a lot of ancillary upgrades, worth it just money. Gotta narrow the search and then shop price/quality
I see lots of Alphas on the road around here since they were made about 80 miles away. Seems like they included a lot for your money when they were still in business. The longer I am around RVs and the more time I spend with other owners I begin to suspect that the "supposed order of quality" that many who post on this forum including me is of dubious quality unless you have personal - first hand experience.
We belong to a little RV club in our area that has just celebrated it's 50th year as a club. Most of the members own motor homes that are not high in the pecking order. But few of our members coaches have many problems. We have lots of Nationals, Fleetwoods, our Country Coach, a Foretravel, two Holiday Ramblers, some old Bounders, and some mixed brands. At total of 30 or so coaches. Only one of the coaches that I know of has blown a motor. That was a Cummins problem though and not a coach problem.
One of our friends in the group has a bounder that looks terrible. Yet it made it to Illinois last year and back with only one repair stop. We have a Dolphin gasser with 167,000 miles on it. Last year it made it to Alaska and back.
My point, most brands of RVs have mostly happy users. As we have already heard from one Alpha owner on this thread that he is a happy Alpha owner. My guess is most Alpha owners are also happy with their coaches. If they were not they would sell them.
Just got back from a 4-day trip to the in-laws house where we put around 700 miles on the Foretravel with a Cummins 5.9 mechanical engine. Got 11.23mpg average for the trip (no toad but two mountain passes). Have one in my 1994 Dodge 3/4T pickup with about 200k (mostly farm use) on it and only one repair job (injector pump). I really like those diesel engines and would not be afraid of buying a coach with that engine (at least about the engine).