Ameriflight allows SIC's to sometimes fly along also, and due to the ops specs it is absolutely loggable by the SIC, even though they are not required.

As to the origional topic, my recommendation to you is that if you want to go 135/91, then go that route. Do not go to the regionals because the contacts you meet there will not be able to help you out down the road. I was a 121 regional guy for 3 years, and am now Part 91, and I got really lucky getting a 135 job out of the regionals... there is a stigma between the two, where 135/91 guys think regional guys are lazy pilots and all that hoopla.

Anyway, I regret leaving the 121 world, but not because I am lazy... for schedule reasons But really, get an instructing job that will allow you to network, and keep getting some SIC time with that scheduled airline. You'll eventually fall into a 135 gig I think. Good luck!