However, I'm considering going back to work at a new Company B that also has a 401k which brought up a host of questions:What constitutes me losing (penalty free before 59 1/2) access to my 401k at Company A?

Hey Eric,About 4 years ago SF passed a law requiring short-term rental Platforms to register all hosts and their rental property with the city, who'd be monitoring their compliance with these new short-term rental restrictions  (must be renting primary residence of min 6 months out of the year; must rent primary residence/room in residence for max 90 days out of the year). 

Why not contact the super hosts in the area where the house is?   

I would look into your area, I know of one (I have never used them to complete an STR purchase) that is called HOST Financial and they require 20% down.

David Greene (podcast co-host) wrote the book on it.  

For airbnb, they do not allow transfers, so we ask the current owner to add us or the new owner as a co-host to the listing to host the bookings.

The REI team I am a part of hosts a meetup as well once a month in downtown Charlotte.

Don't bank with the national guys.It is true that if you work with local banks, you're likely to need a 5% deposit on a personal residence, but you also get a host of other benefits that build over the years by working local.

A few miles to the east is TPC San Antonio, which hosts the Valero Open (large PGA golf tournament each spring). 

Drive for dollars and talk to garage sale hosts.