Apron, The Chief
About the Climb
Sparrow is an old school slab route just right of Over the Rainbow (5.10a) with a few moderate runouts. Despite the fact that there is a short traverse over dirt ledges after the second pitch, the climbing on the rest of the pitches is definitively worth it.
The route starts from the same location as the very popular Diedre (5.8) and Banana Peel (5.8), so don't freak out if you see many parties when you arrive at the start of the route. Should there be other parties waiting for Sparrow, Over the Rainbow (5.10a) is a good alternative to consider.
The Apron has a high density of routes, so there are plenty of options for combining Sparrow with another route. Instead of hiking and scrambling up to the Diedre Ledge, you can climb The Bottom Line (5.9), which is a short slab route that starts right of the trail along the base of the Apron, and finishes at the right end of the Diedre Ledge. It is a great warm up for the slightly steeper slabs found on Over the Rainbow.
From the top of Sparrow there are various options to add more pitches of climbing to your day. If you feel like climbing more slabs, you should go and climb one or more of the Upper Apron routes. The bolts on these routes are more widely spaced, but if you can control your nerves, you will be fine after the 'warm-up' on Sparrow. If you descend along the Broadway Ledge towards the forest, you will pass directly below the Upper Apron. By combining The Bottom Line (5.9) with Sparrow and an Upper Apron route, you can climb more than 10 great slab pitches in total.
If you want to climb something else than a slab, there are plenty of other options nearby. The Boomstick Crack (5.7) starts only a few feet right of the top of Over the Rainbow and traverses along an amazingly thin flake. Alternatively, you can move left along Broadway to the nothern end of the Apron and climb the Memorial Crack (5.9). From both routes, you can continue up and climb either the Squamish Buttress (5.10c) or Ultimate Everything (5.10b) all the way to the top of the Chief. If you combine The Bottom Line (5.9) with Sparrow and some of these extensions, you can climb up to 20 pitches in total, all the way from the base to the summit of the Chief.
Many of the routes on the Apron have some slab climbing sections. Over the Rainbow (5.10a) is a great route, but with more bolts to protect the slab sections. The Upper Apron also has a few short slab routes in the 5.8-5.10a range, which can be easily added to your day if you climb a route on the Apron, and descent by the Broadway Ledge. Another short slab route is The Bottom Line (5.9), which starts direclty off the trail along the base of the Apron, and finishes at the right end of the Diedre Ledge.