Welcome, GT - You've opened a brand new box of fun, although some human conditions impose certain limits, (eyes, steadiness and such,) these are all overcome with patience and learning how to work around them. The aids like Optivisor, or less expensive ones from Harbor Freight to start with, really help with detailed construction and finishing. I have two, one helps me find the other. (:>)
Airbrushing is such an enjoyable way to really finish off a build, and they need not be all that expensive to turn out good results. When I began airbrushing, I was intimidated by what I thought was just too complicated for me to understand.
Actually, careful reading of the manual and lots of practice at dis-assembling, cleaning, then re-assembling the airbrush answers the questions you will have. The three major components of airbrushing are practice, practice and then more practice.
A good place for you to start is by a thorough look at a website, just go to "Don's Airbrush," there you will find a great introduction to the types, brands, use, cleaning and maintaining of an airbrush. I had been airbrushing for decades before I learned about Don's site, then I learned a great deal more than I had known before. Priceless information for me.
With no hobby shops nearby, you will be limited to online orders. You'll find reference to many that are reputable and reliable right here at FSM, and you can ask questions of the other members for places to re-supply your needs. That includes tools, paint, decals and even kits.
I hope you'll enjoy building and advancing your skills as you go. At age 76 I find my vision and steadiness is a factor to deal with, but if I just step away to take a little break and then return to the bench, all seems right again.
Best of luck with the hobby, jump in, lots of fun to be had.
Patrick