Lovely Lake Loop
This is an easily accessible hike with scenic views of Mt. Shasta and Lake Siskiyou. The trail hugs close to the edge of the lake most of the way. There are a few alternate routes to stay as close to the lake as possible, but you'll occasionally wander slightly away from the shore. There are a few bridges that were installed in order to allow for hiking the entire loop around the lake, one of which is a seasonal foot bridge that is removed in October before the winter season. The bridge is located at the delta on the Northwest side of the lake. Keep in mind that this area is only open May through October, so if it is closed plan ahead which direction and side of the lake you want to hike. The southern side has the best views of Mt. Shasta.
Watch for poison oak.
The hike itself is nice and smooth, and varies from single track trails to nice wide trails throughout many different types of trees and plant life. The hike can begin at any point along the route, and there are several parking lots around the Lake to begin. There are many areas where a use trail splits off to access the water.
Access to Lake Siskiyou through entire hike.
Looks like there are cabins and "resorts" on some areas of the Lake, especially the north and East side. I saw a primitive campsite or two, but I don't think this is allowed. There is an official campground on the southern side of the lake which is the only place fires are allowed.
Check out the Official Route and Triplogs.