If you think it is a great deal worth the effort, you could walk through the property with a trusted general contractor to essentially do an inspection before you put in your offer.

If you were to be administering a 20-unit apartment, that might cross the line due to the amount of your effort that would be put in play.You are correct that you cannot work on a property.  

It'll take time and effort and determination and some nitty-gritty, tedious work, but stay in front of the right type of people and continue to provide value.

I hope this reply back isn't too exhaustive, I figured you put time and effort - so will I.Again, thank you for your post. 

If there is no structure with the parking I have not heard of a setback requirement or at least no one indicated such for my driveway conversion.My driveway conversion did not require a curb cut because there is no curb anywhere.My wife did most of the leg work but I think she was expecting the contractors to be cognizant of the local rules so that the plans were unlikely to be rejected by the city.I used the term "looked into" because we got some quotes for this effort so long ago that the quotes would no longer be good and have not done the work (the quotes were much higher than I was expecting but it was a lot of hardscape). 

Now I just don't consider it worth my time unless it's on much larger purchase items or if the effort is very minimal and straight forward.  

The rehab work is what they are willing to put their efforts into.

Is there any quick checks that I could do before putting a lot of time and effort into a deal?

This require $ and lots of effort (as well as time).1) Choose sub to when their is equity in the property, short sale when it is upside down.2) Sub to is a way to control a property without using your own credit and very little money invested (sometimes none)The win-win is created when you get control of a property with equity and are able to lease option it to a tenant buyer with cash flow, and the "seller" gets out from under their financial difficulties.3) Depends on your state, but in CA, you either need to get it from an experienced attorney or another investor who has already done so.

Now we feel guilty.Keep up the effort.