Hi Ashley, congrats on your new move and job! I’d recommend buying your RV after getting to Phoenix. There are a lot of RVs in Arizona in general because of all the snow birds that come down from the north during the summer. Many travel or live in their RVs and when they leave, many people decide to sell for whatever reason.
Also, you don’t want to trust a new vehicle to take you across the country if you’re not very familiar with it yet.
I wouldn’t limit yourself to a brand like Winnebago, just go on Craigslist and see what’s available for the price you want. You can also check local papers. I can almost guarantee you’ll find at least a little bit of variety of RVs for sale in the Phoenix area.
Best of luck to you, I hope this helps a bit! 😀