The term 'indentured' as applied to the Hawaiians needs definition. Contracts between the Royal government and contractors were for short periods, usually 3 years. Wages were specified. The contract could be renewed, but depended upon agreement by the contractor, the Hawaiian government and the Hawaiian involved.
Some left before the contract was completed, but most fulfilled the contract- the money was not fully paid until then.
The labor could be extremely hard (e. g. the hide trade in California) but generally no worse than it was for others in the sea-trades, lumbering and carpenter work, as voyageurs, etc.

The jobs in America were looked upon as extremely desirable. In the 1840's it was almost a stampede. Kanekoa (the governor on Maui) wrote to his (Hawaiian) Ministry of the Interior worrying about the numbers going to California. The Ministry advised Kanekoa to limit the amount, or the island of Maui would be deserted. In 1849, the harbormaser reported 359 native Hawaiians had left as seamen, 8 for service west of the Rockies, and 8 for farms in California. In 1853, 448 men left Maui.

Hard to find but readable on the sea trades are Dodge, E. S., "New England and the South Seas," Harvard Univ.;
Stackpole, "The Sea Hunters," (rare); H. W. Bradley, "The American Frontier in Hawaii, The Pioneers, 1789-1843," Stanford Press.
Best are the various journals- Jour. Pacific History, Reports of the Hawaiian Historical Society, etc.
Well worth visits are the Hawaii State Archives, Iolani Palace Grounds, Honolulu.