Rampart Ridge is impressive from the Commonwealth Basin peaks, but it is actually an off-trail hike with a bit of a scramble move to attain the summit.
You could hike to Rampart Lakes via the Rachel Lake Trail, but it is more direct (and interesting) to go via Lake Lillian.
Take the Gold Creek road (4832) to road 4934, then turn off on a spur road that leads to the Lake Margaret Trail. You could continue all the way to the Lake Margaret Trail, or you could park at the switchback directly west of Twin Lakes. If you do the latter, follow a steep path up to hit the trail going to Lake Lillian.
In any event, once arriving at Lake Lillian circle counter-clockwise (crossing a slab). Find a path leaving the lake and going uphill. Take the path, and follow paths and benches out past two tarns. After the second tarn, ascend to a pass as if going to Rampart Lakes.
From the pass follow paths up to the west, attaining the ridge. Go north until you reach the high point on the ridge. An exposed class 3 move is required to actually get up to the top.
Descend the climbing route, or perhaps drop down to visit the unusual Rampart Lakes. From Rampart Lakes you could descend to the Rachel Lake trailhead if you had set up a car shuttle. Or you could climb Alta.