Instead of a patio, how about an inground firepit with built in seating? Think of a donut within a donut. The top of the seating back would be at current ground level. It leaves plenty of greenspace and creates an inviting outdoor room. Plus, it has less maintenance. The center pit can either be inset or raised to the seating level and be set up for multiple fuels. A ledge around it allows for cooking supplies or cups / glasses of your guests. Installing proper drainage allows for clean up with a hose.