"The other idea I have been kicking around is going to a frac. for a year or two, then try for the majors. Would 48-49ish years old put me out of the running? Not considering the possible age 60 change."

A fractional job would also be a way to go and perhaps even be the post career path you may enjoy. There are many that go from the fracs to airlines.
Airline are not allowed to discriminate against age along with the useual list of others. But often in the interview they will want to see why your age does not correlate to your flight time. That you chose to go into firefighting instead of flying may cause some concern that you really never wanted it bad enough in the first place. Have a good reason in hand for that one.