Hyannis is our preferred destination on the Cape. Good location and a mixture of lifestyles and environments. Cooke's for seafood and Timmy's Roast Beef are tasty stops.

Nantucket has a unique charm. It's delightful. We found Martha's Vineyard to be a nice collection of New England villages. YMMV.

When you say "more time" what do you have in mind?

September is a wonderful time to visit both of the islands. It is less crowded since most families with school children will have left, and the water is at its warmest.

Midweek is the best time to visit because many hotels and guest houses will have three night minimums over weekends. If you want to stay for a week, renting a cottage or apartment is probably the best idea.

It is possible to make a loop from Hyannis to Nantucket to the Vineyard to Hyannis by plane or ferry so you could do a night or two in each, but you won't be able to take your car. Both places have bus service through September, or at least Nantucket does.

I live in Nantucket and love it because the historic town and Sconset are spectacularly beautiful and the beaches are essentially all open to the public. Beach access on the Vineyard is more restricted and only some of the towns are beautiful -- parts of Oak Bluff, Edgartown mostly -- but there is a good bit of attractive open farming country and Menemsha is wonderful. It looks more like a Maine fishing village than Maine does.

Restaurant week, with less expensive gourmet meals at many restaurants, falls late in September in Nantucket, and if you are a foodie, you can eat very, very well for reasonable (?) prices.

When you know more about your plans, I would be happy to answer any questions you might have.

If you do decide to stay in Hyannis, try to get to the JFK Museum there. Otherwise, I'd stay somewhere else.

MV is a short ferry ride from Cape Cod; I think the beaches are easier to access on MV than on ACK.

If you go to ACK, stop into the Whaling Museum; it's really great.

Don't try to visit both islands in the same day; you won't appreciate either, imo.

Consider taking the fast ferry to ACK on the Freedom Line at Sasquatucket Harbor in Harwich Port which is a short ride from Chatham and has free parking for daytrippers to Nantucket.

Thanks so much for your info and advice.
Evelyn