We have never been to the islands and got a great deal to stay a week in Kauii. Our son was under the impression he was going to see the Volcano or lava but that is in Hawaii.
To compensate we want to fly into Hawaii and have the weekend to see what we can in the Volcano National Park before we need to be in Kauii on Monday.
Our plane does not land in Hilo. Can someone with experience recommend the best way to do this?
We really appreciate any input

The best way to do this is to take Hawaiin Air or Aloha Air for an inter-island flight from Kauii. So just fly into your main destination a little early and jump on one of those planes for a weekend stay on the Big Island. You can then be back in Kauii Monday.

Unless you take a helicopter tour, you probably won't see any lava flow.

Even if you stay overnight and hike (about 1 1/2 - 2 miles) toward the lava flow at night, you won't see lava flow unless there is a bench collapse or some other event to alter the current lava flow. You will be able to see a glow at night. But, you probably won't be able to get within 1/2 mile of the flow.

Hawaii Volcanoes National Park is really nice. You can visit much of the park (other than the hike to the flow) in about 4-5 hours.

In a 4-5 hour tour of the park you can see: Visitors Center, Jaggar Museum, Thurston Lava Tube, drive Chain of Craters Rd to the end where lava flow closed the road, steam & sulfer vents, several short hikes and overlooks of craters.

http://www.nps.gov/havo/index.htm

You could expect around $150 roundtrip airfare from one island to another.

7 days or less, stay on Kauai. 8-10 days, maybe a side trip to Big Island.

I've done a day trip (from Oahu) to Big Island. The trip included the park and also a lot around Hilo. Rainbow Falls, Boiling Pots, Lili'uokalani Gardens, Banyon Drive, and Akaka Falls.

I think you ought to stay on Kauai and plan Big Island for a different trip.

This would depend somewhat on what your flight arrangements are. The easiest mode would be to fly directly into Kona, rent a car, drive down to Volcano area and spend a day or two. Then take Hawaiian or Aloha inter-island flight from Hilo to Kauii (it will go via Honolulu), and return home direct from Kauii. Another option would be to buy a round-trip to Honolulu, and then inter-island flights from there, but be aware that while the interisland flights are very short, you still spend a fair bit of time with security etc. I found that using FF miles for the inter-island flights was a good deal several years ago (5K united miles per flight on Aloha).

Accessibility of the active lava definitely varies a lot over time. Check out the national park website for info.

We're doing something very similar in June. We will be staying on Kauai for two weeks starting on a Saturday. We're flying into Honolulu on Wednesday afternoon and have booked an Aloha air inter-island flight to Hilo that departs 1 1/2 hours after we arrive in HNL. We're staying at The Bay House B&B in Hilo for 3 nights and then fly up to Kauai first thing Saturday morning. This will give us two full days to explore Volcano NP and the Hilo area prior to our two weeks on Kauai. I used 20,000 United miles that covered two of us for the 3 inter-island flights we need.

Valuable advice dusty......I was thinking of making a 24 hour trek but will wait till last minute to decide before I blow about $1000 in 24 hours and not have that altering moment of lava flow. Mahalo for candor.

If you are not landing in Hilo then you are landing in Kona and that is about a 100 mile drive roughly to the Volcano Park. Once you get to the park it is another 35 miles til you get to the lava flow. If you thought it was big it is bigger once you get there. It is a crapshoot because the lava we saw was about the size of a campfire. Best of luck.

Looks like we may need to rethink this. Especially since it looks like we are not going to be able to use the frequent flyer miles we planned too
Thanks for all who posted.