Commuting for Part 135/91K is typically on your first and last day of your rotation. Rotations are typically 8/6 or 15/13. There are others as well, these two are pretty common. Be aware that some operators will hook you with that schedule but then inform you that you will commute on your days off.
A predominate amount of 135/91K trips in small jets/aircraft are heavily concentrated and more East Coast centric. There are some more local operators to the West Coast. My experience has been that there are not many, and typically with them you would have to reside at their base. West Coast operations are most commonly to about 25-35 different airports, where in the East there is a lot more variation.
I have worked for both residing at that base and being home based. I worked at one that was more West Coast oriented, but based at home.
When it comes to the commute count on doing coast to coast positioning. If you get less than that, to your benefit. Typically most operators want you to commute in and work a flight upon your arrival. Obviously if your commuting across country this can be a physically impossible. Just understand that you might get to the hotel at 2300 and have an early morning departure. On the flip side when your working on your last day they will try to pack as many legs in as they can before they send you home. You can very easily be forced into performing a 24 hour day, where you don't get home till when you got up the previous day - especially if you live on the West Coast and started your day on the East Coast. Just be aware of these things, and as always YMMV.