I don't brine it before I freeze it. Just shoot, clean, and into a vacuum bag. It's probably 15 minutes between sitting on a branch and in my freezer.

I do brine it before I cook it, though. Basically I just soak it overnight in very salty water. I don't think that makes it much softer, however. The big thing I have found that helps tenderize the meat is to cook them in a pressure cooker. The meat falls off the bone after that so you can just pull it off and use it like shredded turkey. Squirrel tacos have been my best idea so far outside of Brunswick stew.