Hi Susie, and welcome! My best friend lives in and my grandfather lives near Austin--my heart is in the hill country even if my body is in Arkansas!
We actually had a very good eBay experience with buying our 310 RV a month or so ago, but we had a lot of communications with the seller and took precautions.
Bear in mind you will need to have money to spend on your purchase and also money set aside to fix the things that will need fixing before you can really use it. I wouldn't spend my whole saved amount on the trailer and expect it to be flawless. You may even find issues on the way home, regardless if it is just across town or farther out. There is always *something* that will need instant money right after you get it.
But, to me, that is some of the joy of the old trailers/RV's--you learn a lot about them as you work on them, and you get to make things the way you want them.
You sound awesome! I am very happy to see women who can work on vehicles and I'll bet your little farm is just great! You go, girl!
Good luck, and I hope you find your dream soon!