Where are you located, what is your budget, desired level of rehab, etc.? 

The expensive part is most cities require that the vertical walls need to be jackhammered to 2 feet below grade (ground level) and you cannot through the chunks of wall into the pool.

I would say Airdna is "good" from a macro level, i.e. this area compared to another (for ADR and occupancy), but the numbers themselves I would say are not very accurate.

Once you get into your first couple properties, you start running out of funds and unable to scale at the same level you plan on so having a long term strategy on funding your real estate goals is key.

Minneapolis has rental licenses, but there's a grading system for each, and that can often give some insight into the level of care taken by a current owner.4.) read the TISH report, which is required for anything under a 3-unit. 

@Jem Thompson I am going to give it to you straight, coming into the Mpls market, going from 0 directly into multi-unit housing, is of the absolute HIGHEST risk level and stands a near 100% certainty of running into some significant financial impacts.

This was the lowest level agent.

For close in neighborhood demographics, go to a few of the local Grocery stores and sit in the parking lot Friday night after dark, Saturday morning, and Sunday afternoon.Look at the people, and how they are dressed, look at their cars and trucks--guess their income level.

Food, clothes, cars, houses, high unemployment, etc... and no one believes that it is sustainable.   

Mainly it depends on the numbers and your level of comfort and experience in dealing with these older homes.