Aloha,
You have Wyndham points. You can use them on three of the islands, but not in just one week.
My wife and I start from Philly and connect through Phoenix. She won’t do the trip unless we fly 1st class. Fortunately, we have enough frequent flier miles to do it.
I recommend at least 3 days at the Wyndham at Waikiki Beach Walk. It is right in the hustle-bustle of Waikiki, but it is in easy walking distance to the beach all along Waikiki. You can find tours to do just about any water activity. I tend to rent a car for only one day to drive the entire island of O’ahu, but for the first time, a tour would be better.
If you then want the Big Island, I like the Wyndham Kona Hawaiian for a few days. It is not on the ocean, but not far from it. However, most of the beaches in the Big Island are lava rocks, not sand. You can get a helicopter tour to see the island. You can also fly back to the East Coast from the Big Island. You usually don’t have to return to Honolulu from there.
If you fancy Kaua’i for a few days instead of the Big Island, the Wyndham Kaua’i Beach Villas is near the airport and centrally located. It also has a sandy beach. From there you can drive to either Princeville or Waimea Canyon as a day trip. By far, the best brunch I have ever had is at the St Regis in Princeville, but it was $50+ a few years ago.
I would not recommend more than 2 islands, but 3 days in one and 4 in another will give you a better flavor for what Hawai’i is all about, and an opportunity to fall in love with it. If you can do only one island, O’ahu has a little bit of just about everything.
Aloha,
Jim