I think they may have a late chart briefing - Times should be listed in the paperwork you received I think. Even if they don't have one, you might be able to have them take care of it for you depending on how busy it is.

After a long day of travel though, everything else will be much easier if you just order the provisions online. I think you'd enjoy yourselves much more if you took care of putting stuff away, the briefing, getting accustomed to the boat and maybe relaxing by the pool..etc with a drink. Going grocery shopping would be the last thing I'd want to deal with.

What I think you will find is that you really could have just done the sleep aboard. It sounds like at best you might only get there 1 to 1.5 hours before you'd have been able to board with a sleep aboard. And this won't impact your ability to do the chart briefing - if you are at the docks by 5, you might be able to get the boat briefing in though.