I want to learn how to be the most effective and efficient project manager possible so that we can accomplish this in the least stressful way. 

You can often see how much care/attention/time an owner gives a property based on how it's maintained and who lives there compared to other like buildings in the neighborhood. 

I use legal shield for this kind of advice because it is very cost effective.

That way there's incentive for him to maintain it, he gets paid more during the winter, and you don't have to pay for all equipment fully.

I have been considering switching up my portfolio to long term commercial leases, or renting shop space (commercial leases.With so many options out there I was wondering what some of your best headache free real estate investments have been: some examples could be storage units, multifamily rentals, commercial buildings with long term leases, etc.The lowest maintainence ones have the lowest cap rates.

Ask the seller to give you the rent rolls and check effectively with is the amount of every single unit.Are you thinking to live in the property?

I like your repair with accent tile but I also like your idea of a small shelf.Those colorful bathrooms are a dilemma, especially when they are well built/maintained and are in good shape!

I am new to the the real estate investment world and looking to expand my knowledge in flipping houses and maintaining rental properties.

If your goal is to own the property but have essentially no day-to-day involvement in the business of the vacation rental -- you don't talk to potential guests, you don't maintain the calendar, you don't coordinate housekeeping -- hire a real legal licensed vacation rental manager.  

Depending on the shell, it may be more time & cost effective for builders to start anew versus retrofitting existing structures.