Are there any off-the-beaten-track places in Hawaii - or is it all touristy and commercial?

I second the Hana nomination. When you are there, you do get a feeling of isolation and what it might have been like 100 years ago. There is one resort, 2 small stores (2005), (I think) 2 snack shacks (there's a restaurant at the resort) and a few roadside fruit / smoothy / banana bread stands.

There are also Islands that do not get as many tourists: Molokai and Lanai.

If you are looking for low key, there is a little town on Maui called Hana, it is a World Famous drive, Hana Highway, it takes about 3 hours to get there from Kaanapali/Lahaina or Wailea the main "touristy" towns on Maui. Hana is beautiful and you wont find nearly as many people actually staying there as opposed to some of the other areas.

Kaua'i is the most laid back of the islands. It has many unspoiled places. Maui also has a lot of them, as others have said above.

I've been there several times and there are plenty of wonderful places that are free and Not Tourist traps. Ask the locals,they will tell you all kinds of places to visit .

It depends which island you wish to see. Some have the tourist in mind and others, you are on your own.