In my general experience bigger is always better in STR's - do it when and if possible. 

I'm sharing with my husband today, so he can see what is possible. 

.: Quote from @Jesse Dominguez-Castelan: Paul, as licensed agents my team and I do our best to find out as much information from the seller as possible so that we can provide you with what we hope is a complete picture of the property.

I would find that to be pretty much not possible with a high volume listing agent.

That said there are some nuances and requirements to property implement interest tracing so ensure you talk to your tax professional ahead of time and keep the funds movement as clean as possible. 

But because he did poor in RE investing (with virtually every mistake possible), RE investing is not worth it. 

i would:-get the highest paying W2 job you can-save up enough to buy a house hack-house hackwhile you continue to learn and consider the other possibilities you mentioned.

In my scenario I think it's possible the landlord may come ahead. 

@Kristi Wolfe I would be glad to connect with you and talk through possibilities for helping your son purchase a property in Tucson!

@Steve Crisp There are a lot of variables that go into play as to whether you could benefit from a cost segregation study or not.