Assuming my offer is accepted, where would I start?

They stay busy and just going by their house and cars, I'm assuming they are doing quite well with it. 

I assume that you are using an escrow attorney.

@Darren Day I would rather my mother take the $100K in cash at closing than get a few hundred dollars extra per month, assuming that he pays.

You should withhold 5% - 8% for CapEx depending on the age of the property and quality of tenants.I am assuming you are using cash for the purchase and Rehab of the property since you did not include an acquisition loan.You mentioned utilities during the Rehab.  

Assuming you/your property financials qualify.....you’ll need 25-30% equity at that point to avoid coming up with additional cash.

If you do not get a counter, or if the listing agent does not want to discuss this, you can assume your seller is not motivated to sell.

I do wonder if for someone starting out, it would be casting too small of a net to hope they could build up trust with a pretty minuscule audience (assuming we’re targeting locally here...national would be trickier ).  

Assuming you do not have rent control, raise the rent by $50/month, but rather than a late fee, offer a rent reduction - say $50.00 ;-) -  if rent is paid on, or before, the day it is due.We always start the clock ticking on the required Notices in our jurisdictions right away with the assumption we are headed towards eviction until the tenant pays.

@Avery Robertson Yes, you need to take into account you will be getting a lower interest rate and assumingly a lower down payment.