Guys, what kind of insurance is needed, i.e. type/terms/coverage etc for a 4plex in the central california valley?

We are possibly looking to buy a duplex as investment rental property, live in one side and renting out the other side to supplement our retirement income.

Really looking for something to supplement my income and possibly become a full time gig where I can be my own boss.

Yes, it can be used for it, however, I'd suggest investing otherwise and supplementing.

FYI - The quotes do include wind (hurricane) coverage which is a necessity around here.Are these quotes typical?

It is a basic coverage so you should not have to go surplus lines route.  

They over insure, pay out the nose each month for that coverage, and then use the policy for every minor issue that's covered.

I'm now realizing that I could slow down at work and use multiple beach properties to supplement what I would have earned at work and maybe even eclipse my income so that I could work at whatever pace I wanted to.

I have an 8-to-5, but will need to supplement my income when I retire a decade or more down the road -- not to mention the need to put my daughter through college in a few years!  

Our buy and hold strategy is purely for income supplementation and to leverage into additional buy and hold strategies.