In ten years, you may be on the back side of the hiring wave, although it should still be going on. That means you'll get hired, but may not enjoy as rapid seniority progression as those hired today. Frankly, AD retirement is probably not worth it financially since you already have the RC retirement in the bag.

In three years, you'll be in good shape but if the king air gig is going to land you with about 1500 hours FW, half PIC, then you'd be a weak candidate for legacy airlines, at least by today's standards. Cessna time can help you meet ATP mins but won't really enhance your competitiveness.

Bailing now for a regional would get you around 2,000 turbine 121 SIC in three years (maybe a few hundred TPIC if you upgrade at two years. That plus military wings wold probably get you a legacy job.

I think the hard call is between king airs or regional. Obviously king airs pay better and boost the mil retirement points. Regionals I think would give you a slightly better crack at a legacy, but with less pay on the way. Or you could sit tight and wait for AA flow which should be about a 100% bet when your number comes up.