This is one of the easiest and most popular hikes in the Tangle Lakes vicinity. It's 3 easy miles, with very little elevation gain or drop. The surface is wide and well-developed, because it's a 4-wheeler trail. Even with kids, it only takes about an hour to get back to the lake.
When you get within about a half mile of the lake, there a few places where the river comes right next to the trail, with deep pools, good for grayling fishing. At the lake itself, you can catch lake trout, though the lake is really shallow along much of the shoreline.
The trail departs the Denali Highway about 150 yards east of the Rock Creek Bridge. However, the river along the trail isn't Rock Creek but rather the river that flows out of Landmark Gap Lake and ultimately intersects the highway near the Tangle Lakes Inn, 4 miles to the east.
There are several signs along the trail noting sites of archaeological significance. Exploring these areas is discouraged. But if you do, don't disturb anything. Look for the small rises that offer the widest views of the lake and river. That's where you may find old firepits and loose rock chippings.
This trail is fine for mountain biking, but it's quite rocky in the early stretches, so you'll need to thread your tires through the best lines. You should be able to stay on your bike nearly the entire ride.