I'll add that the 100 hours in the last 12 months isn't necessarily a hard and fast rule at DAL...they've hired guys with less than half that. There were two guys in my class who had been at their respective regionals for less than 6 months. One received a call within 2 weeks of updating his app, reflecting his completion of his training at a regional. Both were retired AF guys who had spent their last 3 years flying a desk.
I went to a regional, and I'm convinced it's the main reason I received interviews at the majors. I was a young Guard guy, who hadn't been to IPUG and was only getting ~150 hr/yr. I decided to try the regionals and had 2 interviews lined up, the same day I hit submit on the apps. I actually had a lot of fun, learned a lot about 121 and they even paid for my ATP. Highly recommend this path. Best of luck!