My properties had quite a few issues that were overdue (from previous management) and they've definitely had their hands full with my 'portfolio'.

@ zachEarlier in my career, I did hotel appraisals (market valuations) for two (2) of the largest hotel consulting companies in the world.The short answer to your question which requires a lengthy explanation is:(1)  Find recent hotel cap rates - Companies like Jones Lang LaSalle and others have quarterly/regular reports for hotels. 

The process is ridiculously lengthy.

I have a lengthy Legal Opinion, from my seasoned Legal Team regarding this matter.

I am all for keeping tenants long term and may go slightly under market for retention of good tenants, but this is far too much and it sounds like the rents need adjustments (long overdue)...There may be an opportunity here Philip for some form of joint venture or owner finance if your parents are getting hit with heavy expenses and are less interested in management (adjusting rents, doing tenant turn over and filling vacancies) and meanwhile you are in the construction trades, want to get into investing and have some cash.... 

This might be lengthy but Private Message me if you need.   

Renters insurance will help them out.You're just starting down a lengthy road. 

I have the right to make payments at any time before they are due.These early payments will mean that this Note will be paid in less time.Late Charge for Overdue Payments.

He is able to charge 14/4 because there is no lengthy paperwork, if your deal is good enough you don't have to put any money down, and while it may be expensive, you know he will be there with you at the table for closing. 

[FYI- The township of Bloomfield, NJ Uniform Construction Code: 149-8 has a lengthy document on construction fees & 149-3 has more info on Certificate of Habitability (Occupancy) fees].