This is an easy route except for one little issue: finding a way up through the cliff band at 7,700 ft that divides the lower talus slopes and the upper basin. One option is a narrow hidden gully with maybe 40 feet of Class 4/5 to deal with. Another option is a longer Class 3 gully that starts down and right of the hidden gully. The latter gully is easier to spot from a distance but looks problematic to get to--especially if you traverse the talus slope too high upon arrival at the cliff band.
For the harder gully, the exposure in that technical bit is down the gully. In early season the gully may be snow-filled and therefore easy to climb through. As the season wears on, a moat may form at the foot of that steep bit making for some interesting decisions. By the beginning of August you can expect the gully will be snow-free. It could be wet at anytime. Furthermore, protecting the crux section in that gully can be difficult.
One can choose to approach via Silver Creek for a camp at Silver Lake or via Depot Creek for a camp at Ouzel Lake. The latter approach to camp is easier than the former. However, the route to the summit is slightly longer and requires more elevation gain from Ouzel Lake. For a description on how to get to those respective camps, see the approaches on the Main Page.
Route to Gully
If camped at the east end of 6,763-ft Silver Lake you should be able to see there is an upper terrace a few hundred feet above the lake to the WNW of your position. There are cliffs that come down to the north side of the lake. You can try and climb above them in a northwesterly direction to gain the gully. Or, walk the north shore westward until the cliffs end. At this point turn right (north) and climb up talus or minor slabs to the upper terrace.
If camped at 5,700-ft Ouzel Lake, climb northeast from its north side up the obvious wide gully that leads to the 7,380-ft Custer-Spickard Saddle. Mt. Rahm will be visible to the northeast. From this saddle descend toward Silver Lake. You may not have to go all the way down to the lake. When it is feasible, begin a long slow upward traverse toward the upper terrace on the SW side of the peak. This terrace is immdiately below the Custer-Rahm Ridge (Custer Ridge).
Once on the upper terrace (c. 7,400 ft) continue ENE, aiming for the short 100-ft cliff that separates the terrace from the upper SW basin. As you approach you may begin to wonder how you're going to scale the cliff. Not to worry. There is a narrow gully at an oblique angle to the cliff face that provides access up and through it. You can't really see this gully until you're upon it but suffice it to say it is located where the cliff crooks at an inside corner. The initial section of th gully is slabs.
In the gully
Climb up the gully. About halfway up there is a fork. The left fork looks better (less steep) but it ends at a rather forebidding walled-in amphitheater. An exit to the left might be possible but the rock is extremely loose.
Instead, take the right fork. Not too far from the fork there is a steep section that is the crux (Class 4/5). It can be wet in places. Once above the crux, the gully eases back and eventually you'll ooze out of it into the upper basin like lava from a fissure.
This gully starts down and to the right of the aforementioned gully (see caption and comment for this photo). This alternative is longer but only Class 3. It also leads to the upper basin.
Gully to Summit
Once you're out of the gully (whichever gully you choose to ascend) you're good to go...except for about 700 feet of tedium. There is a snowfield in the upper basin but it's not as steep as it looks from a distance. The easiest (least exhausting) climbing to the summit is probably via the final south spur to the east summit (Pt. 8478). Cross the snowfield rightward to the spur and scramble up seemlingly endless taluscree to the top then go the short distance westward to the true summit. A more direct route to the saddle between the summits can also be made. It will be a little steeper.
Time from Silver Lake camp = 2 hours; Distance = 1 mile; Gain = 1,800 ft.
Time from Ouzel Lake camp = 3-5 hours; Distance = 3.5 miles; Gain = 2,800 ft.
You can descend the way you came. I'm not sure any anchors would exist for which to rappel from in the harder gully. The easier gully may be a better downclimbing option.
Or, you can make a long, high traverse over to Mt. Custer.
Ice axe for early season, else leave it behind. In early season, lightweight crampons for snow (upper basin snowfield is steep enough to be a problem if icy).
Hard hat for the harder gully, or stay out of each other's way. The gully will be the only place you'll need it. I don't know how the easier gully looks. I haven't been in it.