We stayed here the weekend we got engaged (officially - though Emmett first popped the question in the passport office in January). They've got a swim area, the Teddy Roosevelt restaurant and bar, and deep cushy seats for reading.
There are actually TONS of trails - from half-mile flat jaunts to see ancient trees, to meandering 15+ mile moderate loops - that start at the beginning of South Shore road and go all the way to its terminus in a very old ranger's station. Could be a great stop on your way out on Sunday!