I'm getting ready to write our trip report from last week and it'll have costs for taxis, ferries, departure taxes, etc. We keep taking newbies down and I keep track of it so we can give them a rough estimate of what the whole vacation costs.
But I'd add my two cents to the above:
1. Have each couple put $200 into the kitty. It goes faster than you'd think. At 7 nights on the water that's $210 in mooring fees alone.
2. Cooper has a nice happy hour from 4-6. 2 for 1 drinks but only on 3 selected drinks. I think they were painkillers, margaritas and I can't remember the 3rd. Didn't see the beer list, but I wasn't looking either.