In those cases, you may be faced with the question of how to enter a property – and a potentially dangerous situation - on your own.

If the tenants themselves are not the dangerous sort, just messy, I would give it a shot to work with the tenants in turning this around.First, secure the property and try to negotiate a good deal from the current owner as you will be taking over their "problem".

This is a key distinction that many new real estate investors do not fully understand.

Reading the basics and thinking you know the answers is very dangerous in my opinion.  

A friend of mine attests that it the distinction doesn't have much affect on the land value, but I'm curious if that's just in his specific market. 

safe/dangerous?

The cost of a build is so variable in it's many components, using this number for decision making is flat out dangerous.

There is a distinct difference!

But, at the same time, there have to be areas near you which are not dangerous and which still do have 2, 3, and 4-unit properties.  

I just posted over in the Landlords & Tenants Forum about the Dangers Involved in conducting an eviction.