Weather is a big factor for sure. Muskeget Channel is no joke, even in calm seas sometimes, depending on the tidal exchange. The other tough thing in a keel boat is the shoaling that is ever changing there. The main channel is usually plenty deep, but requires you to go far north along Chappaquidick before the numerous shoals to the east are passable. I would certainly try to plan it around the tide- use fair tide to your advantage if possible. Your fuel burn on either the Vineyard Sound or South of Island Route will be more reasonable if you are not fighting it the whole way. 3+ knots of tide are daily occurrences in the Sounds. Wind comment is also true. I recommend looking at a chart of the entire sound first. That will likely tell you what you are comfy with real quick. Nantucket Sound is a maze of shoals.
