Nothing's better than spending time by the water while you're on vacation. Take a picnic to Whiskeytown Lake and then stay for an impressive sunset.
You'll have no end of sightseeing choices when staying in Shasta. Whiskeytown Lake is a great place to start here, but there are numerous other worthwhile sights to consider. Pyramid Lake, San Vicente Lake, and Swasey Recreation Area are not far from the body of water and and will cap off your day nicely.