Although my current boat's a good bit bigger, years ago I did this trip several times in a 23ft SeaSprite. Great trip.
You can't fight the tide at either the canal or Woods Hole. Plan your trip around it (even the days you leave). Ask at local marine
stores for a copy of "Eldridge" - it has all the current information you'll need - a bright yellow book.
Be sure to have a radar
reflector. The fog
can close in quick. A lot of boats around.
You might want to consider a night in the Sandwich Marina in the tiny "harbor of refuge" basin at the east end of the canal. This isn't pretty (next to a power plant) but you may not care after a long day. Showers and pretty good restaurant. No anchorage space - you need to call for a slip reservation.
Buzzards Bay can be really rough in the afternoon when the a southerly sea breeze is up and the tide's going out. Duck into Onset if that happens (Onset is a very good alternative to Cataumet).
You will probably decide to go through Woods Hole because it's much more direct. It's not hard (and kind of exciting) as long as you and your crew study the charts
carefully first and then confirm each buoy number as you go through. There are a lot of buoys and it can be confusing. Again - can't fight the tide - over 5 knots at times.
Four days is probably the best pace. 1 - Scituate/Plymouth, 2- Cataumet, 3 - Hadley's Harbor, 4-Vineyard Haven.
Adding a day for Cuttyhunk is great fun.
Getting to the Vineyard could be upwind all the way. This can feel really long. If you get a northerly day make all the miles you can. Also, motor
a few hours in the early morning if the wind
hasn't come up - you'll be glad you did at the end of the day.