I'm a Certified Surgical Tech.
I have no kids, but I can fill you in on the job details.
Some of the places I've worked staff 24/7 hours with no calls and no weekends if you are not on that shift. Usually those are LARGE hospitals in big cities.
Most techs do take call, but you know ahead of time when you will be on call and you can plan accordingly. It is just like a scheduled shift. OR people learn quickly to get caller ID and not answer the phone when they are not on call and away from work! LOL!!!
If you have plans on going on the nursing school, I would recommend you go straight on to RN school.
I LOVE being a tech. I have travelled, taught, made excellent money and learned loads. Even still, I recommend going straight RN for folks with those goals in mind. For you it would mean just one period of seperation from your son.
Make sure whatever CST school you choose it is FULLY accredited by CAAHEP or ABHES (with CAAHEP being your first choice). It is important to ensure that a diploma/degree from your school will allow you to sit the certifying exam. You can work without certification, but it is a important extra that may make you more marketable.
Talk to schools about clinical locations and guidelines. If it is a night program, will CLINCIAL be at night? Most hospitals prefer students during the day because the night shift is usually very slow OR full of "knife, and gun club" members. It is hard for a student scrub to learn in the middle of a trauma case. Additionally, you ideally want your clinical throughout your program and not tacked on at the end as an "externship".
I admire your courage for going fo that better life.