Hi time4me
I would never put myself in a three day long party situation at a beach house at 52 days...sounds more like an ordeal to me than a test - but whats done is done.
My only advice is to let people know, loud and often, that you're not drinking.
I understand you might not want to tell everybody
why but try at least to find one 'sober buddy' if you can & stick to them.
Focus on the fishing, tubing, skiing, barn fires with smores, and pig roast - play with the kids...anything but drinking.
Let us know how you get on
D