I work a ton of Californian investors here and most usually start with turnkey, then move to value-add, and then larger multi-family. 

Fortunately, I live in a HOA and the HOA has been very proactive in recommending vendors that they have worked with or have approved in the past.

Can someone recommend a good company that works with traveling Healthcare professionals? 

No fee, no agenda, membership - just networking. 

I raise this because there’s no true regulations and it’s truly the Wild West of lending with tons of questionable participants. 

If the second property you are buying is not turnkey, will require some work, and there is a clear value/range of what you can bring the property to by adding value then you can refinance to pay back the majority if not all of your HELOC (used for downpayment or to buy the property completely).You'll need to know how to analyze an after repair value of the property to figure out if that technique can work or not.

Then, the plumber will scope to ensure no compromises in the line.

That will help you move forward in the path that best fits your needs and not waste your time pursuing strategies that sound great, but not work for you.

I'm concerned that if I place an ad to find people who will work on an hourly basis (in the area of the property) that I might have a hard time finding people who can reliably respond to emergencies during off hours, but I can't afford to have someone working full time or with standard on-call rotations. 

But I'm also curious about what has worked best for each of you and why!