I understand there are sq. foot restrictions based on the loan type.  

I also need a system that can help me manage my sales opportunities and pipeline, and is fully customizable to meet my specific business needs.I am particularly interested in learning more about how Salesforce can help with all of these requirements, including its integration with Google contacts, drip campaigns, and automations.

By actually, I don't mean teaching you how to theoretically (SEO, "we buy houses" campaigns), I'm talking about them actually getting a property in your hands at the right costs.

Now a historical area on the other hand, with restrictions... this makes me look at what I will have to do and the extra steps I would have to take to do it. 

I think if you were sharing walls or in same house, then certain quiet hours in lease or noise restrictions can help prevent some issues. 

To me the quadplex would be dual purpose, while you are not living there it serves as a reliable stream of income, once you move there, you could live in 1 of the units while you build your permanent home, and you could also use it for when your family comes over for large gatherings.A 2nd option might be to build an RV park, Unless their are zoning restrictions, you should be able to build one fairly inexpensive, with a septic system and either public water or a well, you can keep your costs to a minimum by doing gravel roads, which are easier to remove later if you don't want them. 

Here, you should be obtaining a geotech report and reviewing the title report and the zoning  to verify there are no deed restrictions or zoning overlays. 

Companies like Wal-Mart and Jiffy Lube, as well as Realtors have already been hit with multi-million-dollar lawsuits for sending non-compliant (illegal) text messages without proper (required) consent, or opt-in.You don’t want to risk finding yourself in the same situation, which is why adhering to compliance regulations is so important, so make sure if you are using SMS Marketing for Real Estate, be sure your next campaign is compliant.https://reimachines.com/sms-compliance-for-real-estate/

The local markets depending on where are talking about or have put in restrictions on STR's.

I’m aware California is not the best market, with the restrictions and potential new tax coming up, etc, but we have personal reasons to invest there.With that said, we visited a lot of houses in the San Diego area and saw 2 that seem like a potential fit for us: one is a smaller 3 bedroom but a mile from the beach and the other is a 15-17min drive to the beach, but bigger with 4 bedroom and a little cheaper, which would allow us some cushion to invest on a hot tub or potential pool.