Prices are just to high relative to rents and incomes.

In the grand scheme of things, yes, you should eventually replace the windows so 1) They operate properly. 2) It doesn't turn away potential tenants or cause maintenance hassles when a new one moves in.3) Tenants have proper egress in case of an emergency (like fire).Now, windows are expensive, so you'll have to decide how much you're willing to spend, based on how much income the property is bringing in.

What works for travel medical professionals is different than what corporate renters are looking for, which is different than insurance placements, etc. etc. 

I do feel foolish for not understanding that all the deductions that real estate has to offer, could only be used against real estate income.

The tenants are low-income and may not have banks.

Of note, this is not my full time income, as I do have a full time W-2 job. 

List your income, costs, and savings, and think about options like FHA loans or NACA or Loan Depot.

And have a great credit score and a steady income but I have a mortgage on my primary as well.

Does anybody know if my father can prove his income to a lender when I try applying for an FHA loan instead of my income?

Dominic Kosteris worked two jobs and lived with his parents before buying his first home in 1996.In 1997, he acquired his first investment property and started earning rental income.