I did an 1 hour dog sled with paws. The hostess is very nice. She has about 40 dogs. They are very cute and you can have close contact with them. They provide clothes and pants which keeps you from the coldness. During the ride, you can also ask to stop for pictures. If condition allows, you can also try to drive the sled.
There are not many activities in winter Alaska and this is a good one. I also see the dog mushing in Chena Hot Spring. This one is much better I'd say. Chena one is shoter and relatively expensive. If there is not enough snow, they are not doing the dog sled. Thus, I highly recommend this one!