If I were in your shoes, I would consider using a property manager.  

What was found is that now the economy is coming back shoppers go for higher end retailers in those areas so the bread and butter for dollar stores is the lower end areas where they really thrive.The downside is when the DG goes out or moves etc. the second or third generational tenant isn't paying what they pay for rent.If I was in your shoes I would seriously evaluate whether you want to stay in this deal or not.

Maybe it's because I'm socially awkward, but, I'm wondering--how would you approach investors/patrons at this event in my shoes?  

I spent today, an amazing spring afternoon, strolling around the historic district of Fletcher Place with my wife - a veritable stones throw from your office, I know. 

Just THINK put yourself in their shoes.

My financial planner sweats bullets every time I talk to him, reassuring me that the market is going to go up, up, up, that this is wise investing for the future, that everything is fine.That guy drives a BMW, lives in a half-million dollar house out in the sticks, and really likes glen plaid suits, double cuffs with cufflinks, and the kind of overly stylish business footwear that I refer to as "clown shoes."

What are you asking the seller to do - call you, send you financials, etc.I don't share my letters, but as a tip, what you need to do is put yourself in the shoes of the seller.

Once at someone's house, I would collect all the letters and postcards people got and sometimes they saved them and it filled a shoe box.

You should honor your contract.That is the problem with Arbitrage, when things are not working out, people want to bail on their obligations.What if shoes were reversed and owner wanted to cancel their contract with you after you had built a successful business?

Take it slow for a couple of years, do 1 or 2 deals at a time.If I were in your shoes I'd look at spending around half of this money on a steady cash flow apartment complex or commercial property in an 'A' location with around 50% leverage.