It really sucks to bleed cash and live in a job site for 2 years, though. 

I have a discount on my site if you are interested.

Zillow is the biggest real estate website but it helps listing on other sites. 

Also check out BiggerPockets sister site for passive investments: www.passivepockets.com 

Do a search on county assessors site and with the city to determine empty lot plans/issues.  

Who is responsible for cleaning the construction site and keeping public walk ways free and clear of construction debris since you are in CA without the ability to monitor the site?

We do Urgent cares all over the county and get pitched med office spaces all the time, and none fit our profile for visibility, for our use at least, only because we follow a more "retail" modeled approach to site selection, given the business type.  

I have placed on all the free sites and start getting requests but is slow, any ideas or experience on which works the best?

They don't connect with a lot of apps and other vendors though, and their site and services are clunky. 

I have won on all of those sites for clients, but your time will be better spent somewhere else.