Long-time reader, first time investor from Rhode Island!

I need the real story on vacation rentals on The Big Island, HI...specifically the Kona area. 

Its an island sticking out in the SF bay..

For instance, one property seems to have an extra bathroom that is not listed in the county records.I plan to make some modifications, including removing a closet wall to expand a bathroom and taking out a kitchen island that contains electrical outlets and a switch.

My specialty is working with investors and business owners in locating island based cash flowing rentals and or non rental second homes. 

I have a lot in East Rockaway, corner that I am helping the owner find a buyer...Trying to get more info on like zoning and how much you can build, Property shark has been useful in NYC but pretty useless in Long Island, can not even find basic info there, is there another website or resource I can use for more detailed property info?

It is on the boarder next tourist areas and the island.

Interestingly, I live in my community (Marco Island) with my short term rentals and have for years.  

Where we go down is a side branch which has shallow water, next an island and then the actual river.

@Bryan Cavellier, You can 1031 with any US property including Guam, the USVI and ...drum roll- The Northern Marianas Islands (go figure but I actually had a realtor from there in a class of mine recently) into any other US or one of those territories.  1031 is a federal statute so it's applied the same in all locals with just a few variations state to state at the state level.