I'm in a lucky position in that I can either bid to be home or not. For the most part, though, your average pilot is going to be away from home 12 days a month. That would be for someone who chooses not to live in base. If you live at your base, and bid reserve, you can be home a lot more.
For me, I live in Spokane WA. We have two day trips out of Spokane on my plane (757), though one is going to da Bus (A300-600R) in April. Since I'm senior in my seat (5 out of 120), I can get one of the Spokane day trips if I want. It's not all Spokane flying in those schedules, but I'd only be away from home 4 days a month if I do a mostly Spokane schedule. They don't build trips with just flying out of one city that much.
I don't really like the cold winters in Spokane, so right now I'm in Guadalajara doing LAX turns. It's a day trip, too, and I get a company paid ticket to and from work. I'm away from home about 12 days a month when I do this trip.
I've rambled on....
To answer your question simply, I'd say a freight guys number of days away from home is similar to a pax carrier.