As porqueno stated PHX is the only Dash base. With PBS you can request anything you like, getting it is another issue. Some months there are a lot of day trips others not so much. I believe the junior bases for the CRJ are HI (all), IAD and ORD (not sure which is more junior). If you are looking for PHX then it will be a while to hold it on the CRJ as I know guys with 6 years seniority that are bouncing between RSV and a line and as the 200's get parked it will get even more senior.