I have already commented on Trip Advisor so I will keep this briefer.
$60/person for a trip to Pt. Barrow is actually pretty reasonable for that area I would think. You have to realize you are VERY remote. Bring some of your own food or you will be in for MAJOR sticker shock.
I believe the Stan Stephens Columbia Glacier cruise is 7 hours long and I think you will be disappointed. You won't get to see the glacier, just icebergs. If you want to take a glacier tour from Valdez, taking the Meares/Columbia Glacier tour is a much better choice.
And yes, I think your kids are going to end up getting a negative impression of Alaska with all your driving. Just MHO.