CTM is a great rate, can learn a lot of technician work as well as networking. CTR's are a great rate as well but probably more diverse than than CTM's, most CTR's do desk analytical or signals collection work. Can also go on subs/aircrew. I don't actually know if CTM's go air crew/subs, but R's definitely.
Both CTM's and R's can be attached to NSW. CTM's can do a lot of cool stuff with NSW as well, but a more limited than the CTR route dpending on where you go. At a basic level you're either going to go to Development group or Special Reconnaissance Team, missions are highly classified but you're supporting Special operations command so you get the idea. However, it is not guaranteed by any stretch that you can get in these programs. They're screened programs and require you to be in shape and have particular personality types, which are screened for as well.
CTM's are mostly going to be on ships or maintenance type commands that provide troubleshooting assistance to the fleet. East/west coasts are the obvious, or anywhere there are ships. Also opportunities for NSW.
A school shouldn't be an issue really. It's at corry station and is a ton of fun in my opinion. Enjoy it.