When paying down debt Dave Ramsey has been a good influence for many people.  

It may be substantially more simple.

I would instead look out-of-state for A and B-class properties offering much lower C-on-C returns but with minimal maintenance needs and tenants who on balance would have much more substantial and regular incomes.

Now my question is, how can collect that money, should I hired a collection agency company or what other means out there to collect money she owes, also I don't want this to influence other tenants make them think that they can get away not paying rents but at the same time I don't want to spend one more dime trying to collect from her and not getting anything.

.- If you'll likely be selling to a DIY updater, or someone else who wants to add value to the property AND there is substantial value to be added (through updates throughout the home) AND your market will bear the additional price, then don't do the repairs.  

If you hold long enough to pay down the mortgage substantially, collect some ongoing cash flow and get a little appreciation you will do fine. 

I also know that I could really make substantially more overtime and I am comfortable getting this converted to commercial land and developing it.

Personally, I like How to Win Friends and Influence Others, if I was to choose 1 book to gift a grad. 

Overall you'll have a portfolio that is worth substantially more than what you paid for it and bringing in great income. 

The loan officer needs to be experienced, and the lending institution needs to also be reno-minded (IE, has to be a substantial amount of their business and have all the right departments to go with it).