The Big island + Maui or Kauai?
 

My family (husband, 12 yr old daughter and 8 yr old son) and I are going to Hawaii next August for 8 nights. We will be using Starwood points and are definitely going to the Big island to hopefully catch a glimpse of active lava. This would be the primary reason for our visit. We plan on choosing a second island to visit, either Maui or Kauai.

My questions are:
1. Would you recommend staying 3 or 5 nights on the Big Island? Because we are using Starwood points, if we stay someplace for 4 nights, the 5th night is free.
2. We are looking for spectacular beaches and the possibility of seeing marine life (turtles, dolphins, etc.). Would Maui or Kauai be better suited for our family?
3. We'd stay at either the Sheraton Maui or the Sheraton Kauai. Is one of these hotels much better than the other?

Thank you!

I love Maui and there is probably a bit more to do for a family on Maui. The Sheraton on Maui is in a great location for activities and restaurants.

At least 5 nights on Big Island. Plenty of sea life including manta rays right by your hotel. I'd be tempted to stay on Big Island for all 8 nights as there's so much to see and do and it would save you the internal flights and time wasted moving between islands/hotels.
You could split your stay on Big Island (5/6 nights at the Sheraton and 2/3 nights in the Hilo or Volcano area to reduce the drive time).

The Sheraton in Maui is right on the beach and has good snorkelling.

Stay on the Big Island and enjoy. Don't count on seeing flowing lava and hopefully you will be surprised with a gift from Pele.

Eight nights is little enough for BIG Island. Stay Kohala Coast plus a night or two in the town of Volcano. You may at least see some 'red glow' after dark. In addition, if you are coming from farther than the west coast, Day One in Hawaii will be largely adjusting to the time change.

Every transit between islands will run about $100 pp and will cost you *time*: 4 - 6 hours door to door.

Reserve your rental car soon. On an island, when they say, "Supplies are limited," they mean it!

I agree with ChiSue, stay the whole time on Big Island, lots to see and do and because it is so big there is a lot of driving involved. Most people stay a few nights in Hilo or Volcano and the rest of the time in Kohala.
Not much to see as far as lava, other than the glow from the lava lake at night, usually viewed from the Jaggar Museum, so have realistic expectations. Conditions have been this way for a year or more.
Have a good trip.

Thanks everyone! We may have to regroup and consider how we want to spend our time. Flying from island to island is a huge expense but want to make the most of this trip (we are celebrating my 40th birthday).

The Sheraton Maui and the Sheraton Kauai are actually very similar - both a low-key resorts right on very good beaches. I believe the Kauai one has been remodeled more recently than Maui. The Maui Sheraton is in the Kaanapali Beach Resort, which is a development of condos and hotels starting with the Hyatt Regency at one end, and ending at the Sheraton and Black Rock, a distance of about a mile, and connected by a paved beach path. Halfway between the two hotels is Whaler's Village - a small shopping center with some decent restaurants. North of Black Rock are more hotels and condos, but you have to get around Black Rock to get to them. The Kauai Sheraton is on an excellent beach, and across the street from a small shopping center with decent restaurants. There's no beach path but it's also more laid back.

At least from what you said, if you spent eight nights at your hotel you'll get two nights free. Can you extend your trip to 11 days?

I agree with others who're saying you should adjust your expectations for flowing lava on the island. The action is usually underground, and what little is visible from above ground (usually holes in lava tunnels) is made invisible by bright sunlight during the day. Your best and in most cases only chance for viewing lava is in the evening, helicopter tours are best/easiest to avoid hikes.

For first-time or one-time visitors to Hawaii I usually recommend Kauai, especially people who mention spectacular beaches as a priority. Because of the Big Island's youth, almost all of its beaches are lava rock or an uncomfortable mix of lava and sand. Water shoes are required for swimming even at the Four Seasons. The island does have a few amazing white sand beaches, e.g. at Hapuna and Kauna'oa, and if your hotel points can get you there or close to there I might reconsider the Kauai rec.