One thing that does turn me off is difficult access in and out of driveway and or garage.

I am also a Real Estate agent with Keller Williams with access to the entire market. 

My broker is an investor as well, but he gave me access to the MLS...... looking for tips for criteria to narrow down the search results.

In my area (outside Baltimore/DC), you better have one eyeball on the MLS constantly because if they do appear, there are there for a nanosecond before being snatched up.I say this because my point is an agent that invests and understands investors/investing is going to be networked into that community and will know about deals that don't see the light of day (i.e., the MLS).  

I'm not sure what access they give to non pro/plus members. 

You need to understand your market, controll your contractors with good contracts, have access to good financing, and know your after repaired value. 

Is it the MLS (which I heard you need to be a real estate agent to access)?

"The market" (any market) to operate at maximum efficiency requires that all actors have complete access to information.  

So if you get a great deal on a house and post purchase (due to either it being a great deal or the rehab you completed or both) it is worth meaningfully more, you can't access that equity for 12 months.  

Soon (hopefully), it will no longer require the applicants to go through the SmartMove authentication process, and will instead give the landlord instant access to the credit/criminal/eviction report directly within the Buildium platform.