With regards to traveling nurses, I was mentioning them as a potential tenant pool if I decide to purchase a STR, as an alternative or supplement to vacationers as occupants. 

Unfortunately you're not paying him enough (and he's not charging himself enough) to stay on your project all the time so he has to create supplemental income.

(click to enlarge)Bottom LineEvaluate the property based on whether it will enable you to achieve financial freedom.

You are enabling her.

Rather than wasting it or leaving it in a bank account I'm interested in starting my own investment business to supplement my real estate sales. 

In these cities, your financial resources will go a long way enabling you to assemble a diverse multifamily portfolio and initiate a steady stream of income.

Also, many clients are going to a 1-man office staff that is supplemented with a kiosk.

I am certainly not a tax expert, but fwiw, I just looked at my closing statement from the purchase of a Brooklyn multi-fam and as purchaser, I paid the following taxes:Transfer Tax Additional Transfer(mansion)taxTransfer Tax Supplemental NYC(mansion)taxMortgage Tax 1st mortgage

Having accurate figures will enable you to make informed decisions.

@Nathan Gesner, having that line of credit will enable to you make a quick purchase, should you find a gangbusters option OR to handle damage from a storm, or what-have-you.