Owner owes 110k property is worth 70k .

The time and effort, road blocks and struggles associated with starting with nothing are seldom worth your efforts. 95% of those starting out will fail.

The networking alone to expand your business thru contacts that you meet at the conference is worth it!!

You can try and take them to small claims court later if you feel like it (its not worth it) but if they move out on their own volition and don't damage the place that is usually the best you can hope for.

This debt alone is an asset and worth considering. 

Yeah, I’m having a hard time believing you want to cancel because you had some “potential extra risk”, you did agree to let them do some work, as opposed to you think the house is worth more now.  

My question is, is this worth it?

If single family home do a survey and check for boundary violations etc.Unless you are getting a sizable discount this may not be worth the effort.

Maybe you'll get lucky and find something.Disclaimer: Consider this 2 cents worth of advice as I'm no expert so it may be all it's worth. :-)

The new measure is aimed for the November ballot and would certainly be worth paying attention to as it develops.