I bring all of my animals out of the field to do the skinning, you just need to find an good place to dump the carcasses afterwards. Some people do eat Beaver tail but I personally do not. Lately up here the big tails are being shipped with the fur but they have to be wider then 4" I beleive it is.
As for the Mink stretcher, I make wooden ones as both the females and males have to be stretched on different size boards up here, not sure about where you live. Depends on the Auction house most likely.
When drying the pelts you have to be careful not to dry them to fast as they will become very brittle, same goes for if they are left to long on the boards. The pelts will actaully start to shrink so much they tear around the edges where it is pinned or nailed. Once the pelts are dried remove them from the warm air and place them where the mice can not get at them as the will chew them up. Had this happen to myself this past year. Hung them in the same place that I always have only to have the mice attack my coon pelts.