Cambridge, the forecasts for the US mainland seem fairly certain about wind and weather systems moving to the east for the next week, so I would also expect the storm to be on a reliable track and unlikely to move further west than forecast.
Question being, what speed are your friends making? 7 knots? 9? And at their speed, where would they expect to be on Thursday 2pm, when that depression is still forecast to be south of their track? If they can be fairly clear of it 24 hours before it gets that far north, I'd say go for it. And, of course, get an expert opinion from Herb if they can!
If they duck back east, it may wind up adding a week to their trip and still leaving them with sloppy weather.
For yourself, if you're staying coastal, I'd gamble on the depression staying further east of you. Which can still leave you with weather, just not in the thick of it. With the massive heatwave forecast for the US east coast...I'd say coastal tornadoes are the thing to beware. (Excuse me, they're not tornadoes until they make landfall, yeah, sure.)