Well let me speak from experience. I am a surgical tech first assist, and I'm currently in an accelerated BSN program. Yes, you may have a lot of standing at times, and some times you sit down. For example carpel tunnel and hand surgery procedures. Some times on long femoral popliteal cases you sit. Secondly, as one person above stated about running around, once your case is open and you are scrubbed, the RN circulator does all the running and fetching. You stay in one place. Anyone who works in surgery knows that.
As far as surgeon relationships go, most of them will love you. You have douche bags on every field, but they respect the tech who knows his/her stuff and they rely on you. They love when their cases go smoothly and you play a huge role in that as the surgical tech.
Pay: Techs do not make more than RN's. I make more than new grad nurses only because I have been doing this for almost 10 years. But even when they start out, they are only a couple bucks under me. They get several dollar shift differential which puts them higher than me on any given day. (one of the many reasons I'm going back. They won't hold a Candle to me once I get my RN, and become a RNFA)
If I had a choice, go for the RN. You have more opportunities and avenues. If you can get through school, you will find a job. Live and make your own experiences. Follow your heart and be happy. Don't let fear of a hard class our criticism of your age stop you. Everyone experience is different.
Always pursue your dreams. P.s. I have 3 ladies in my cohort who are 57, 58, and 59. Second career girls that's all, and that's ok.
Take care and I hope this helped you.