Another way to look at it also is if you have a rental and you can increase rent by $100 and sell it in a year for a certain value, are you better off selling it today at another value or holding it for another year and collecting income?

Anyone can declare real estate losses against their active income if their income is under the AGI threshold but only someone whose PRIMARY profession is designated to be a real estate professional will be able to offset active income. 

Current income is only 1100 a month.

Tax considerations involve a lot of personal, specific considerations so you are on the right track going for a CPA (make sure they are familiar with income properties and short term rentals).STR is a business and involves "active" income versus "passive" income associated with typical long term rentals.A few general things:1.

I am aiming to overfund the initial purchase if I can to cover property, repairs, assumed mortgage cost for months of no income (assuming 6 months max), and any variance.

Short term capital gains is your ordinary income tax rate and long-term capital gains where you hold the property a year or longer is considered long-term capital gains is in as taxed a lower rate.  

Renting offers steady $4,000 monthly income, long-term property value growth, and potential tax benefits.

My current property manager doesn't instead sending a monthly ledger with the month's payments (company name, pay date, amount) as well as monthly income/expense statement.

Our goal is to (eventually) have a second property where we can spend time at our retirement, and that can generate some income as a short-term rental for a portion of the time when we're not using it. 

See example below: DSCR < 1 Principal + Interest = $1,700  Taxes = $350 Insurance = $100 Association Dues = $50  Total PITIA = $2200  Rent = $2000  DSCR = Rent/PITIA = 2000/2200 = 0.91  Since the DSCR is 0.91, we know the expenses are greater than the income of the property.