You will round Barrier Lake quite quickly and rise slightly as you then begin the approach to Lesser Garibaldi Lake. Either lake is a good place to refill depleted water bottles as necessary. Of course, be sure to treat your water. Both lakes will be quickly passed as the trail here remains relatively gentle. After Lesser Garibaldi Lake, the trail will begin to rise again as you make the final approach to Garibaldi Lake. You will pass two more junctions on your left as alternate routes to Taylor Meadows make themselves apparent. Both are clearly marked by park signs. Continue straight along the trail and, approximately an hour after you reached the 6 km marker, you should approach Garibaldi Lake.

At the time of this writing (Sept/99), the main bridge crossing the Garibaldi Lake outlet river had been washed out, so a detour had been cut adding about 5-10 minutes to the trip. The well marked detour cut slightly higher and further than the original trail, coming out along the north side of the lake at the existing Black Tusk trail. At this point, cut back down and back to a temporary bridge at the lake outlet. Take in the splendid view of the lake and the glaciers on the mountains on its opposite side. Cross the bridge, turn left, and another five minutes will have you at the camping area.
UPDATE: During a trip to Garibaldi Lake in September of 2001, I discovered that the detour mentioned above had become the permanent trail. There is now only one crossing over the Garibaldi Lake outlet.
There are about 50 camping sites. If they are full, the rangers will likely have a sign stating so. If this is the case, you will need to hike back to Taylor Meadows (the "overflow") and camp there. If not, find a suitable camping spot and pitch your tent. Most of the sites are good, but if you can, avoid ones close to the outhouses. Smell isn't a problem, but the constant sound of opening (creeeeeeeak) and slamming (BANG!) doors can be annoying. Trust me, I speak from experience.
This area has four huts, or shelters, in which you should do your cooking and cleaning. There are also ample outhouses. During the summer months, June through September, the cost is $5 per person per night (this changed in 1999; it used to cost $7 per night regardless of how many were in your party). You must pay in cash and in advance at the self-registration box near shelter #1, so be sure you bring an adequate supply of $5 bills, depending on the size of your party. The rest of the year there is no charge to camp in the park, but keep in mind conditions are quite extreme outside of the summer months and only the most experienced of hikers should venture into the park between October and May.
Garibaldi Lake, September 1995. 6:30 a.m. Just a few minutes before the sunrise.