Seems in the ballpark to me. I looked over my direct deposit history and I was at 1900/month take home but single with exemptions set to 0. Also, 0% 401k deferral with a little state income tax paid.

Supplemental income: you'll likely have the weekends if that works for you. Otherwise, it may be possible to sit reserve and somehow make money online. However, most bases I've been to don't even have Wi-Fi.