1) I have been flying for the regionals for a year.
2) I intend to fly for the regionals for 2-3 years total.
3) I don't know about my "threshold." That mainly depends on the market at the time that I'm looking to get out (1000 TPIC). Right now, if one of my "top 3" wasn't immediately possible, I'd take the first LCC/Legacy to give me a job. A good corporate/fractional gig would also be tempting.

My advice would be to round up your contacts to see if you have any chances at the big iron...if not, hit a regional and hope you hit the upgrade quickly so you can move on.

Good luck.