At one point I had called them; in fact they have a website. JimW - thanks for taking the initiative to call them. Among the questions we should ask:
a) what capacity per cabin?
b) group sites?
c) proximity / location / conveniences? (Good report from John M)
We should probably be prepared to make individual reservations if the group dynamics won't work. Another creative approach is to make it a family thing, lodging nearby to indulge in fishing activities as available.
I'm sure some / many with boats will run across from Vineyard Sound shoreline from Woods Hole to Cotuit.
Also, those heading to the island should work together to minimize the vehicle / ferry costs to the island. Pooling high occupancy vehicles is the best approach. Shore fishing opportunities are good on the island.
Hmmm... a shore slam deserves a good prize!