Also as mentioned most folks on this site do focus on dwellings of sorts.

So I found on the county website this...R-6 These districts exist for the protection of areas that (General Residential District) generally contain older residential structures, some of which were originally large single family dwellings which have been or may be converted to rooming houses or multi-family dwellings, and others which have been built on relatively small lots.

They are also subject to rules governing service termina­tions to multiple dwellings, customer security deposits, payment agencies, back-billing and the refund of overpayments.Municipally owned water suppliers (those of cities, towns, villages, etc.) are not governed by the Public Service Law.

Additionally, there are no laws stating a dwelling must provide appliances.

Relevent text:The owner of a dwelling is required to post a notice which is constructed of durable material and which is no smaller than 20 square inches in size listing the owner’s name, address and telephone number if he/she does not live in the dwelling or have a manager living in the dwelling.

The zoning key words you will want to look for are "Accessory Dwelling" or "Principal Building".

Previous insurance company doesn't want to insure the property anymore because the main dwelling is empty. 

Which makes me wonder why here in Los Angeles there is an extreme housing shortage, rents are going through the roof, the state recently passed an law making Accessory Dwelling Units easier to build in an effort to mitigate the the housing shortage, property values are at a level at or above the housing bubble peak. 

Make sure it’s a dwelling policy and not a homeowners policy otherwise if you rent out your place you’ll void your insurance

So if a dwelling cost on average 20k to bring to average condition the market will discount that property much higher then 20k allowing the frugal and knowledge rehabber immediate equity.