The job is really simple once you get into it. You literally have templates for everything you will be working on and if you don't, your supervisor or someone else will have them. The only thing you will have to learn is how the process for everything works. That will take the most time and even some NCOs I know, that have been in longer than me, don't know what I know. Meaning, you need to learn from each other! Share your experiences! You will also be working at different levels throughout your time in the Army, so don't go into your next location thinking you know how it all works because the Army operates differently at each station. You will have the general idea of how it should work though.
Overall, I enjoyed what I did and where I worked at. I started at Ft Lewis then went to Japan after my deployment and have been at Ft Meade since 2014. Each place had it's pros and cons, but just know that the Army is like any other job where it will have its great days and then its shitty ones too. Don't get discouraged though and embrace the suck as it could just be a learning experience. It is hard for us to get promoted to SGT and SSG as points are high, but you can do it. You just have to want it! I got too complacent as a SPC and started to see people pass me by and then had a reality check, but as soon as I worked my ass off for the points I needed, I got promoted within 4 months. You'll find those SPCs though that I was like at every duty location. Ones that just get complacent as to where they are. No need to really make rank, but think they know better. Sure I knew a lot because of being a 42A and the experiences I went through at Lewis and in Iraq, but I was still a dumbass for getting complacent and not applying myself. That's one thing I do regret.
Chances of you getting overseas isn't that hard. Korea is always open and Germany is right there too! I would actually try to avoid Hawaii. I was there for a TDY (think business trip) for a month and yes it was great, but to be there longer than a month would kill me. It's just too small and sure I was stuck in Japan for three years, but you cannot drive around Japan in 2 hours so there was a lot more to do and see there.