I'm not a regional pilot, and have no 121 time at all. But here's a funny related story:
I was talking to a recruiter for Allegiant at a job fair in December.
He said; " You should go to a regional and get some 121 time. Then we'd hire you in a second." (I have 8000 tt, 5000PIC, 4 type ratings, good 4 year degree.)
Me;"Well, I'm in the pool at Atlas. Would 747 time count?"
Him; "Ummm, yes! A year in a 74 and you'd be ready for sure!"