While we are away, should we simply pay off the mortgage (it will take me approximately 5yrs based on my calculations of additional payments I can afford).

In addition there is likely little or no competition because you are buying this as a private party sale in an "off market" transaction.

Then spend time learning on private lending.

Three year option to extend for additional $500/month.

Keeping detailed records of expenses also facilitates easier tracking and analysis of spending patterns, which can be invaluable for budgeting and financial decision-making.

Additionally, there's a large STORAGE 10x20ft unit in the backyard.

Meaning you mathematically adjust for the higher overhead costs; if you have a bigger rent payment due at the beginning of the month, then you need to be making more cash flow to accommodate the additional risk.

Not trying to spend an arm and leg on this... 

I wouldn't recommend land flipping as a strategy unless you are prepared to entitle the sites and spend money on soft costs to have the sites shovel ready.

Are you going to be paying him more than he’s collecting in rent or is selling to you going to result in a pay cut for him even before the additional taxes.If you have other properties (you mentioned selling for the downpayment.) why not do a 1031 with those properties for this downpayment.