Hey Matt, hope you and yours are OK! You guys have really gotten pounded this week! Unbelievable!
How did you marinade your butt? Was it a brine, or a marinade? (There's a big difference).
Either way, you'll be OK to freeze it until you get off the Ark. It should survive the next 40 days in the fridge.
If you used a brine, rinse it really well under cold water, dry it, and vacuum seal it (if possible). If it was a marinade, you can rinse, or just package and freeze. Marinades only flavor the surface, whereas brining penetrates the meat and involves salt, so you want to rinse that off the surface as much as possible.