For your questions, go to their web page.

I know there's QB web.  

Imagine your investment sitting empty collecting cow webs while still paying that enormous property tax, granted the owner probably bought at low price but still.

First thing we did was identify the largest 20 cities in Massachusetts (you can easily find that information in the web, but here is the link to the official 2010 Census).Second we identified average home values and rental prices for each town (there are several sources for this information, Zillow Research is one example)Lastly, we divided average annual rental rates in each town by the average cost of homes in those towns. 

Start by reading their web site if you haven't already: https://www.wilmingtonlandbank.org/It looks like they have a requirement to live-in your personally rehabbed property for at least 5 years. 

If Zillow went away tomorrow, other web sites would pick up the slack.If you prefer staying on Zillow, offer to pay the $10 fee for the manager so he can continue marketing that way.

Are there any web listings that you could recommend.

Their web page is nothing fancy but don't let that dissuade you.  

Eventually I want to do everything through a web portal but I'm not there yet. 

Three words...NetworkNetworkNetworkConsider a "We buy houses" capture web page.