I have found that it is quite simple to self-manage a portfolio of 30-40 short-term/interest-only loans using a combination of QuickBooks and an XL workbook (1 worksheet "tab" for each loan). 

I worked for a property management company that requires all potential tenants to check into the main office prior to showing as a means to provide a safe showing for the employees.

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

I've been doing revenue management for over 10 years now (hotels and STRs).

During the partnership, you can jointly manage the property, increase its value, negotiate a flexible repayment plan with the seller that allows for larger payments after the property appreciates, ensure a written agreement that clearly specifies repayment terms and timeframes and refinance, and the sellers are able to 1031 at their leisure? 

Quote from @Andres Lasaga: I am in the process of selling a property to the tenant I have been renting the house for 4 years.I want to outsource the promissory note collections and reportsIt would be only ONE property, for now, any recommendation of a company that can manage the collections and reporting?

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.

But, if steady long term cashflow is a goal, with no management, one can always sell farm land on a low down private contract.

And knowing a thing or 2, I'm gonna assume you are good at the details, and at managing paralegal team. 

The other 2 duplexes I have purchased have had no issues.Larry and Josh were working with me as well for 2 years then they just handed over the communication to management company and vanished once 2 or 3 year mark hit.