If you've done many historic home tours, you will find this one unremarkable. It's not bad, but you're not likely to learn anything you don't already know. The tour guide was exceptionally enthusiastic, knowledgeable, and helpful, and the house is interesting, but it's nothing special as these things go. The two most important things: (a) you will NOT actually get to see insight the guest house where Robert Frost vacationed; and (b) you should not waste your money on the "historic homes tour," a package deal which includes the Heritage House Museum, the Audubon House (also worth skipping, unless you're really into Audubon) and Casa Antigua, which is the biggest rip-off of all (it's nothing more than a trinket shop selling island kitsch, with a pre-recorded and rambling audio history of the building (which is also nothing at all special).
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.