Verizon is not a GSM network and coming from Canada (or almost any other country in the world), the OP almost certainly uses GSM.
So, the big two carriers you will be able to buy a SIM from are at&t or t-mobile. There may be some more local/regional carriers. You can go to the t-mobile website and find a realistic coverage map - provided by a third party - to determine if they have decent coverage for the island/s you will be on. (at&t by contrast, will look really good on coverage since they just throw up a generic tower map and allow you to assume that the signal strength is consistent regardless of terrain, interference, etc.)
You will probably just price compare the two when you get there. I'm guessing t-mobile will be cheaper. Keep in mind, you will have to buy a month of service regardless of your length of stay. Also, don't rule out going to a local mobile phone shop that sells service from multiple carriers (t-mobile, at&t, etc.). They tend to be more helpful and flexible.
If you want to play it safe, you can figure out if t-mobile or at&t works best for you and contact them ahead of time and find out all the details of what you will need to do and where to go. There may be activation waiting times, etc. I don't think you will be able to do anything ahead of time unless you know someone locally in Hawaii that can help you out.