First, keep track of how much the delay is costing you. 

You would be surprised and some of the returns you can achieve with a minimal upfront investment.

Are you saying that he'll only require you to make the 300k Construction loan payments for the first year, in essence delaying the $1.4M note payments for a year? 

This choice costs you the minimal amount of interest you'd save had you used the funds to pay towards mortgage instead. 

The dream would be to set up a system for him to retire on my properties and take minimal stewardship roles in my name.Dad suggested that I line up some agents to look at properties that I'd like to acquire and operate; I've been on Zillow/Trulia for sale price and Trip adviser and AirBnB for Rental rates doing comparisons.

Usually there is a period where only owner occupants can bid, which helps to eliminate competition from investors and helps revitalize neighborhoods by minimizing the % of rental properties.

What would you do with 250k of capital that is minimal work with maximum payout?

This is the "Delayed Financing" rule.For example, if you buy a home at $50k, put $20k of repairs, and the ARV is $100k then you would be limited to receiving $50k + closing costs.

Good points--right now with units in the basement I have to pay that laundry water usage–and the money from the coin laundry offsets that and then minimal income per month.If I was to add laundry to the units, all water usage could be passed on to the tenants, thus saving me that expense.

Some of the really old homes have them and they really do work at providing some airflow and extending minimizing the need for heat and air in the spring and fall.