The first tax benefit of real estate is that the cash-flow and appreciation grow tax free(in general).Cash flow will likely be offset by depreciation and appreciation is not taxed.If you are making 8% on real estate(combined cash flow and appreciation), you money will double  in 9 years.If you make 12% on real estate, your money will double in 6 years.There are other strategies in real estate(time involved in real estate) where you can create 'paper-losses' to decrease your W-2 wages, interest, dividends.I normally don't like this route too much as I think people can focus their time and attention more on other tasks that can generate a higher hourly return.Best of luck.

You could still get the tax deductions...rents will likely go up, interest rates will likely stay flat or decrease slightly, Austin has a great outlook long-term. 

What other scenarios could I possibly run into besides property value decreasing that could cause issues?

We haven't noticed any decrease in bookings.

Is the population growing or decreasing in that market?

It looks like you have a business loss which you can use to offset other forms of income.I don't think you sold it less than its worth, you likely tried to get as much as you can.Squatters decrease the value of a home, especially if you are selling the house with them in it.

For instance, Sacramento CA has seen very little change, whereas Phoenix and Tucson AZ have seen a much larger decrease in revenue. 

One way or another, however, the investors must work to pay down loans, increase rents and decrease expenses wherever possible.

Evaluate historical and current vacancy rates, aiming for decreasing trends.Demographics: For younger populations, focus on proximity to parks and schools.

If you pull permits and renovate, both your property taxes and insurance are very likely to increase, causing your cash flow situation to decrease.