I recommend moving closer to the unit and suck that MPA teet while it still exists. Gain experience and try to become as much of an expert in your weapon system as you can. Fly your arse off and upgrade to AC. Become more of an asset to your unit and not a long distance problem child (not saying that you are one now...). You never know when the airline industry will tank... again. If your unit likes you and you work hard, you could be one of the first people they want working there full-time if for some reason you're furloughed and need to keep the lights on. We've got a few guys who try to do the whole guard/airline thing while living 500+ miles away and as a fulltimer, I can say they're a bit of a pain in the rear end, but when you live that far away from your part-time job, the part-time job will be what takes the back burner when your other life gets busy.

I say all this understanding how important seniority is, but I don't think doing the regional thing is the answer. Your path to PIC time is quicker in the C-17 and it's 4-engine, heavy turbine time with worldwide mobility responsibilities, which will enable you to bypass the regionals in 3 years or so. With 40,000+ airline pilots slated to retire over the next 25 years, the majors will definitely still be hiring in 2019. I don't think we've even seen the explosion of hiring that will happen in a few years. They'll only be able to deplete the regionals so much.

As an ART with the guard, I've made more money in milpay this year so far as an O-4 +12 than an 8 year FO with ExpressJet. Other than one 30 day rotation to the desert this year, I didn't really have the option to suck up MPA either. I'm not pitching the full-time thing at all because I have an app in with a major airline right now, but I'm saying you can make good money as a bum doing cooler stuff for now. Sounds like you're young, motivated and not a bitter/jaded, crusty old major or Lt Col yet so take advantage of that while you've still got the drive.