Average days off 14-15 for line holders. 12 days off on reserve; FO's are on reserve now about 6 weeks. The schedules can be commutable, but that depends on how you bid. We have a preferential bidding system that builds your schedule to your specifications, seniority permitting. If you make it a priority to build a commutable line, it'll try, but that might mean that you can't get the days off or the trips you want. The more senior you are, the more likely it is that you'll get what you want. There are no published lines of flying as such. They're all built on the fly.
The reserve shift is assigned the day before it starts by crew scheduling. If I recall correctly, they'll give you a 12 noon to 12 midnight shift on the first day of reserve if they can. Call out time is two hours. By the last day, you'll probably be on a 5am to 7pm shift, but if there's nothing for you they'll release you early, by perhaps 3pm. They actually do look to see where you are in your work week to give you the most time off that they can. They know that most of us commute; in fact, some of the schedulers commute. Even though you won't be on reserve long, they try to make it as painless as possible.