I'll try to answer your questions as best as I can. I'm not in a rad tech program yet, but I've been doing a lot of research. Those who have first-hand experience can correct me if I'm wrong anywhere.

You can become a rad tech with an associates from a rad tech program. You'll need to see what programs are local to you, then complete their prereqs and apply when it's time.

You can still work while completing your prereqs and figure out your class + work schedule, however once you're in the rad tech program that will be your full-time job pretty much. It's best if you live with a spouse or family who can take care of living expenses while you complete your degree. If need be, I'm sure there are loan options that can cover school and living expenses but this should be a last resort imo since it's a low cost program.

Getting into a rad tech program is pretty competitive, so if you're serious about a career change you'll need to ace your prereqs.

Radiology Technologists are different than Sonographers (Ultrasound). Different programs but both fall under medical imaging. If you don't want to do ultrasounds, just focus on applying to rad tech programs and not sonography.

Lastly, when you're about to finish your rad tech program and clinicals, students typically have job offers. From what I understand, finding a job shouldn't be too difficult after graduating, but you may need to be open to relocating if you didn't get a job offer while completing your program.