And to be safe, I'd make certain (if you haven't already) I had a good umbrella policy to cover potential damage in the event a tree lands on his yellow Corvette. 

Having said that, having the base liability insurance of $300-500k along with an umbrella of $1M seems more than sufficient.....assuming you’re not running some slumlord operation. 

You could add a table & umbrella on the deck.

From his profile:My Industry specialties include: RE Investors, Flippers, Contractors/Builders, Realtors (E&O), Property Managers (E&O), Multiple Property Portfolios, Commercial Properties, Personal & Commercial Umbrella & Excess, Lenders and Flood Insurance (Both through the National Flood Insurance Program & Private Alternatives)

(As an umbrella question)How does the actual cost of capital compare?

You mention material defects, E&O, umbrella policy, etc.

As your assets grow you'll want to make sure you look into an umbrella policy but if this your first and biggest asset your liability coverage on the homeowners policy should be sufficient, just make sure you sit down with an agent to make sure the policy properly covers the property for how you plan to use it. 

I would absolutely suggest an umbrella liability policy.  

RE is under the financial industry umbrella in commerce.

I still haven't been convinced by anyone (through multiple discussions) that an LLC provides better protection than a personal liability umbrella policy.