But I’m not insensitive to the security issue: I wouldn’t want unvetted, unaccompanied strangers walking through my home. 

This is something that will be hard to judge at first but once you start getting the hang of walking a property, and doing the flips you will be able to estimate off the top of your head when you walk into a place.

Who is responsible for cleaning the construction site and keeping public walk ways free and clear of construction debris since you are in CA without the ability to monitor the site?

We recently did a sealcoat project at one of our properties and a resident walked across the wet sealcoat.  

Then walk away.  

Give you your $10k and walk with a $10k.

If you can't get the seller to reduce down to that appraisal, consider walking away. 

Learn how to consistently hit singles and doubles, and don't be ashamed to take the occasional walk. 5 years is a very short time frame to go from no RE to financially free (although you may already have property, which is an awesome start). 

@Steve Rosenberg - I appreciate your comments and am considering a video walk-through for future tenants.  

Regarding the elevator, you will not be able to rent to multiple people who can't walk up that many stairs and you might get negative reviews about people having to carry their luggage.