I've had a Maine CCP for many years now. There's a fair amount of paperwork to fill out initially, but once that's been cleared they issue you a 4 year permit (unrestricted) in the form of a laminated picture ID. Simply download the application forms and follow the directions. Unlike my neighbor state to the south (MA) they're quite nice to deal with.
Not sure about the non-resident option. But I can tell you that a backlog of about 5,000 new permits was recently cleared, and our Governor has made clearing apps a priority. I'd ask you if you'd looked into reciprocity, but you're Glenn, and that would be a dumb question.