Depending on the age and/or enthusiasm of your kids, I would recommend Hannegan Pass or Skyline Divide. Hannegan Pass is a pretty mellow 3 miles (about 1000 feet) with Ruth Mt. dominating the head of the valley. From camp, you can head up the pass to even better views. Skyline has more elevation gain but you have the advantage of being on Mt. Baker with a great view up the N. flank and across the valley to Shuksan (and nice ridge camping). Weekend rules apply to both.