From PEOPLE Magazine Click to enlarge
After a day spent racing through the desert-hot streets of Albuquerque, dangling by rope off a rocky ravine and then dodging venom-packed rattlesnakes in a dust-choked canyon, a girl's gotta have a place to get away. For Mary McCormack, who plays U.S. Marshal Mary Shannon on the hit USA drama In Plain Sight, her on-set trailer gives her respite from the chaos and, more importantly, precious playtime with daughters Margaret, 6, and Rose, 4 (she is expecting her third child in September with her husband of seven years, Brothers & Sisters producer and director Michael Morris). It's a working mom's domain: brightly colored sticky notes with a long list of curse words her character is allowed to utter line one wall ("They're 'basic cable friendly,'" she laughs, "and I use them to get into character because she's pretty foul-mouthed"), while a bright orange construction-paper clock created by Margaret hangs on another. "She's learning about time," McCormack says, during the few moments of time she has before heading back out into the heat.

Do you have a routine in here?

I always have coffee and The New York Times, which is wishful thinking because if I have lines to learn, I can't look at the paper because I feel too guilty. I come in, drop my stuff off and grab my script.

How did you select the furniture?

Our set decorator Carla Curry is a friend of mine and knows what I need. I got a low table for the kids so they can do crafts or a lesson if I'm on-set. It's great to come and see them here.

What do the three of you do?

We draw, paint, read, play hide-and-seek-the cabinets around the room are great for that-and have pillow fights in the little bedroom. Margaret was 1 when we did the pilot, and Rose was 8 weeks old when I came back to work, so they've always known it and they love it here.

Is it a struggle as a working mom?

I'm lucky. I get to do what I love to do in a business where it is really hard to make your way. I've nursed babies on-set and in the hair and makeup trailer, and that's how they've grown up. I have girlfriends who drop their kids off in the morning and don't see them until bath time. So I've been really lucky. When my kids stop by the set, everyone is happy to see them.

Ever cook anything in here?

No. I microwave old Starbucks from the morning. High glamour!

What's in your refrigerator?

Low-carb sugar-free diet stuff-from when no one knew I was pregnant-that I don't eat because it's not natural enough. Now it's all fruit and water. And juice boxes for the kids.

Does pregnancy make it tempting to fall asleep in here?

I never really have time to nap. The bed in here doesn't get a lot of action. I'm still pretty active: The other day I was climbing down a ravine with just a rope-it was pretty physical and that was pretty silly. I probably shouldn't have done that. But it's fun to play a character who is pregnant while I am, and it's nice to tune in and see a real pregnant person. This is what real women look like knocked up. It's not all in the tummy!

The baby is due in September, and you'll be back to work a few months later. Will you add a crib?

I've had two babies in trailers before, and I usually set up a changing table on the counter and a Moses basket in the bedroom. That's really all you need!