Chopper is a very recent (48hrs) foster, so he's having some separation issues as is. On the 14th, the fiance and I are leaving for a planned-for-a-year vacation. We're attending a music festival and have had our $100/night no-pets hotel booked since last year, so Chopper needs to stay behind for four days.

Not sure what the best way to go about this is…
I'm planning to just board him in a nice kennel in the area (Suites, beds, outdoor play areas, private runs, and 24hr staff.) and hope for the best.
No one I know is comfortable watching him, with his biting and crate screaming, and leaving him home with a sitter is definitely NOT an option (he screams, howls, digs, and whimpers all night long, as is, screams the entire time he's in a crate, and I live in an apartment.)

Any thoughts?

take him in to the kennel for a weekend.
It will cost you some $$ but you will be able to see if he can "handle it" or you will have to get someone to move in and keep company with him.