Everyone is pretty relaxed on the islands so just stay away from the touristy areas and you should be fine. At worst, ask a local they will give you any info you need and more.
My Dad was from Maui and I've been there numerous times but only once to Big Island, if you have a chance make it to the north shore it's gorgeous. Also Hilo is really neat, it's almost like that city is stuck in another era. Kona is pretty touristy but 15 mins either way and you're in the country.
I would kill for a malasada right now! OMG!