Wifey has a place in Orleans, right on the bayside beach (Skaket). Nice town, far enough out without getting killed by traffic on 6 past the rotary, the beach is perfect for kids.
If it's just the two of you though, you might want to go further up. Tougher to get in and out but once you are up there Wellfleet is awesome, Truro is really nice and quiet. P'town is nice to have close for dinner options.