I currently house hack with a SFH, but I'm researching ti decide what my next RE project should be based on my preference and market demands.

I Just dont know where to start , hard to find comps, but given how many people have asked to buy this farm I live on, there must be demand for it where I am at.

I have a tenant with 2 certified service animals (dogs).

Although, they may widen their search if there are a lack of similar sales in the Subject's market area.Based on what you are saying, the properties located beyond your property's zip code and within the 1-2 miles radius, are in a higher demand market area, with greater market appeal and therefore higher values - for some reason.

Should I reach out to tenant and demand that we are not renewing lease and they should quit?

Flex industrial product has been in good demand in this area, and there hasn’t been much available.  

Make sure you get a "Release Fee" on each property; this is an amount that is to be paid to release a property as collateral in the event you need to sell, or if you have an insurance loss that insurance proceeds will be applied to the subject property and not to the whole loan keeping you stuck with an encumbered damaged property, remember they don't make construction loans as a second and the blanket loan won't subordinate (usually) to another lender, it could get messy, so have a release fee stated and understand how payments will be applied.A line of credit is not a blanket mortgage but a line of credit can use other collateral, different animal and it may or may not fit you needs.

Despite what a few have said, I've seen prices and demand here remain relatively steady thanks to proximity to SF Bay Area and Lake Tahoe.

As long as there is a good thesis as to why the demand will remain high for shorter stay rentals  and most importantly (1) the use is allowed, (2) the use requirements are protected by in place permitting and licensing and (3) the permissions are transferable through a sale you will be on the right side of the supply/ demand equation.

New builds typically tend to appreciate faster and demand a higher rent than average for an area compared to older units (we often see a higher quality tenant(s) in new builds as well).If you were to buy an already built 4 plex are you expecting any immediate or mid term rehab and what are the projected rent rates and rough estimate for annual appreciation.