Should I talk to a contractor first to see what it would cost, or an appraiser to see what they would think it would add in value to the home? 

As long as you carry adequate insurance, as a landlord this means at least $1-2 million GL or umbrella per occurrence plus defense costs, the LLC's "protection" is never going to come into play.

Closing costs would be around $16,000.

I have a lot of interest in the boutique hotel space and have found an on-market property near me with huge potential and lower entry cost than any other deal in the area.

Attempting to manage it from a distance is going to cost you a lot more than the PM fees.

Over the years because of California insurance regulation policies, companies like State Farm were unable to raise premiums fast enough in these areas to meet the current insurance costs. 

Quote from @Mica Moore: If you are not prepared, self management may cost you more than a good manager will charge.

(this is called reserves) On a 300k price 15% is 45,000 but you would need closing costs and the required reserves for your particular situation as mentioned above. 

Context: I'm entirely invested in low cost, diversified stock index funds, and I expect them to earn a~8% CAGR on a nominal basis.

Construction costs continue to be out of balance in markets near me.