No experience other than harbor day sailing, new to you untested and unfamiliar boat, outboard of unknown condition, offshore for four (or more) days. I think that would qualify in my mind as foolhardy. That's not to say you couldn't do it, just that it would be hard to think of too many more things that could make for an "interesting" experience. With a good weather window and the ability to get into port each evening and a good check out of the boat and systems it's certainly doable. Good luck to you whatever you decide.
SV Laurie Anne
1988 Brewer 40 Pilothouse