One think I would watch out for is asbestos since the units are so old.

I do watch flip shows & I know things can come up.

After reading through that myself, I really enjoyed reading Brandon Turner's books that you can find here on BiggerPockets under the Education tab,  in "Books & Resources". 

Yes watch out for those who can't spell and with bad grammer. so easy to tell these people from the rest.

Welcome,Hope you do well and enjoy making great retirement resources.

A lot of people watch for the specific towns and zip codes to see if someone is working in their area. 

Your intro will make you popular, everyone needs a good carpenter in this business.I'm new too, and would say read all you can, post in forums a lot, which helps you to network, and watch as many podcasts as possible!

I enjoy setting my expectations low, commensurate to my RE-investment knowledge, but plan to self-educate through biggerpockets and other networks.  

I enjoy listening to the podcasts and going through the new posts on the forum.

I doubt that everyone who has their house listed for those really high rates is actually booking--you might be able to get an idea if you keep an eye on some of them and watch to see if those weekends book up (some of them show the specific weekend available).