Hawaii is a small chain of islands with a very small population. Hypothetically speaking, if the Imperial Japanese Navy's Combined Fleet were to have launched the air assault, and then a naval invasion, it would have been possible. Remember that Japan was able to invade the PHilippines in 1942 , which had a large American naval force, and over 80,000 American soldiers defending the islands. At the same time we were able to conquer Singapore , which boasted over 110,000 British soldiers and and an 'impregnable' defense guns.
Hawaii, compared to these was minor. At most, the American military base in Hawaii had very little defenses in terms of land defense. Taking Hawaii would have prevented the catastrophe in Midway from happening.
One has to example the cost / benefits relationship. The cost of taking the islands would have been minimal compared to the benefits. Taking the islands would have permanently knocked out the Pacific Fleet, delaying the American counter-offensive for quite some time. On the mean time, the Imperial Navy would have secured the sea lanes in newly conquered Pacific. The merchant marine force would have tapped into the resources (oil, gas, metals, etc) of the newly conquered Dutch East Indies, Malaya, Thailand, Burma, Vietnam, Philippines, China.
Remember that the overall plan was to secure resources to fuel the complete conquest of China. Hypothetically speaking when China was conquered, the Military Command aimed to mobilize the entire Chinese colony to fuel the Japanese War Machine. Chinese men would have been conscripted to join the ranks of the Imperial Navy, Imperial Army. As what happened for Korean and Taiwanese conscripts that served in all branches of the Imperial Armed Forces.
These "what if" scenarios are interesting, aren't they? lol