Does is makes sense for use as a landlord to have a security system installed to monitor each of the 3 units or is this something we should leave up to the tenants? 

TV software, servicing companies, First Nat Acceptance, Marc Gold has a new service that will handle all aspects including tax monitoring, title curative, foreclosure etc.  

Now you'll just have to verify all the numbers, look into the infrastructure and determine the tenant base in the park.

I was leaning that way, but I'm not able to monitor the project or have a good enough handle on the repair costs to know whether or not I can get my money back out with a refinance to go out and get another place and cover the HELOC.

If so, you’ll need a way to monitor their performance. - annual and turn-over inspections: your handyman can do these with proper direction and a checklist.

I've had a basic security system installed, and the first 12-months monitoring is included in rent (this drops on renewal or for the next person -- a built-in $25/month rent increase for me :-). 

They may be good candidates for financing a property for you, but they are much less likely to be in distress.There are list companies that monitor people's credit scores and send you their name when it drops a bunch.

They have the ability to create much bigger profit margins than you would ever be able to generate building out the infrastructure and trying to sell homes yourself, or worse, just rent spaces.

There are real-time radon monitoring systems.  

To Sacramento, you've got more tech, startups, white collar jobs, etc. coming to town because the infrastructure is already there and it's a cheaper - yet still cool - alternative to the super pricey Bay Area.To Stockton, it's probably going to be more middle class non-techy jobs that are more easily replaceable with relatively the same income from city to city.