Why pay off the mortgage early? 

If not, what are property tax sales? 

You can then measure the cash flow impact versus the potential cash you would obtain upon a sale.

Here are some general guidelines: Lien Position1st Position LienEquityMinimum Down Payment of 20-25% (a 30% equity to sale price is preferred)Down Payment made in certified funds and not borrowedMaximum Funding of 70% ITV (Investment to Value)SeasoningMinimum of two monthly payments already made12 months or more preferredPayer CreditCredit Score of 650 or higherNo major derogatory trade lines (No 90-180+ days delinquent, foreclosure, repossession, bankruptcy, etc.)No decline in credit since purchase of businessTermsPrefer 60 months or lessMaximum of 72 monthsNo Balloon Payment preferredCash FlowBusiness has positive cash flow1.25 debt service coverage ratio preferred.DocumentationPersonal guarantee from a creditworthy individualStandard documents including Note, Security Agreement, and UCC-1 filing.Tax Returns on the business that substantiate profit and loss statements.OtherPayment history current and verifiablePayer Interview indicating buyer is satisfied with business and comfortable making paymentsMotivation for selling the note is not a result of a deteriorating businessConsideration of high risk businesses or geographic areasIn these situations, sometimes a partial is a better option. 

Your new ARV(after repair value) should be supported by an adequate amount of comparable sales in the area(duplex's).

Steady pay, you can learn how to manage property and deal with people, and you'll be licensed to handle sales on the side.

I learned about them from a Rent to Retirement podcast where they interviewed a former W2 FT sales guy in tech (that's me today...) turn real estate investor.

Quote from @Cameron Moore: Exactly. 15 years ago, I noticed an increase in owners using insurance to pay for a replacement roof, usually to sweeten the pot during a sale.

Purchase price: $70,000 Cash invested: $60,000 Sale price: $70,000 Have under contract for $70K and will rehab.

For the son to qualify for the $250k exclusion, I believe he would most likely need to meet the ownership and use test, meaning he needs to own and live in the home as his primary residence for at least two of the last five years before the sale.