Check their occupancy, nightly rate and amenities.

Low out of pocket cost. 

This book has great information on how to evaluate deals and will tell you about the metrics you are asking.

The vast majority of your wealth gain in real estate will be by holding properties long term and the appreciation/principal paydown will slowly but surely help you become wealthy.For 90% plus of people out there who are looking to start, house hacking is the best way to go.

@William Fishergreat question thanks for posting, I was just looking around for posts that were related to this.

I would get a slab/foundation company out there to take a look at the property and see what the quote is to repair it.

Get as much info as you can. get their bank statements see what comes in and comes out.

Now that's out of the way.

While it seems possible thats true, people doing this are screen shotting stuff from Zillow.

Although multi-family properties is a term used more in the US and converted itself into a proper investment strategy, this is also possible in Spain (or anywhere in the world).