Welcome and congratulations. As you probably know and will hear in other responses, you need a copy of the 2013 Eldridge. Maybe you've got it already. A little study of its tables and current charts
and you'll get what you need for the canal and for Buzzard's Bay. The breeze usually picks up pretty well in the afternoon in BB and is usually from the southwest, but you could find it coming from any direction on any given day. You will read in Eldridge and in other guides about what can happen when you clear the canal and with the current at your back and the SW breeze in your face and the water being pushed up into the current. It can get pretty hairy. So, again, avoid those precise conditions on the day you go through if you can. Plenty of places to stop overnight on the way. You could do the whole trip in one day with good conditions and an early start, but why not check out Quisset, Hadley Harbor, or Marion etc on the way down. Or go to Cuttyhunk, which you'll love. Other than weather and seas in adverse weather, BB is no problem navigating, pretty much a straight shot unless you are entering any of the BB harbors. My boat moored in New Bedford and if you need anything in that harbor when you pass by, let me know. I'll let others comment about Narragansett Bay. If you get stuck for crew and need another body on board, let me know. When I got my boat a few years ago, I brought it down from Beverly, MA to New Bedford, MA and that inaugural trip is still a great memory.