Just wanted the opinion of more seasoned investors.

Will be a better question for your CPA in my opinion, they'll have better visibility into what strategy will work best before filing season and EOY. 

Still strong but lots of competition, so you need to research what works: good pics, seasonal pricing, amenities, etc.

I have a more educated wallet and that makes me feel real good.Whether you’re a seasoned investor or just starting out, these lessons could change the way someone approaches their next deal.

Number 1 reason for non-rental is $ price of rent, second is the season, I say the season is Thanksgiving to Super Bowl. 

Other than comps for 3-unit properties (which are typically not furnished and operating as STRs), how would most seasoned STR investors look at valuing the property?

All this can happen within 30-60 days unless your town has a specific perc season and you don't have sewer access.   

overall 50% book rate for Dec that still may go up slightly (especially the zero booked unit is likely to book for Christmas).There is a reason it is called the off season.

My firm has a 3 month seasoning period that will get you up to 140% of your purchase price and rehab costs. 

BiggerPockets is full of resources designed to help you along your journey, whether you are just getting started or a seasoned investor.