For a slightly more exerting route from Chinn's Lake try the NE Slopes. This is especially nice if you plan to also hike Mount Eva and/or Mount Flora during the same day, to cut down on RT distance by 1/2 mile or so.
From I-70 exit 238, Fall River Road, follow the exit ramp to Fall River Road and turn right. Follow Fall River Road 6.7 miles until a turnoff on the left to a dirt road. Drive on this dirt road 2.4 miles at 10,400' to a "Y" junction. The last mile to Chinn's Lake is on the left-hand (southern) 4x4 road at this intersection.
4x4 or hike to Chinn's Lake on a southern spur road approximately 1 mile SE of Fall River Reservoir.
From the SW side of Sherwin Lake choose a route straight south up the NE face of Witter until reaching the ridge. From here talus hop SW 1/2 mile on a SW angling traverse to avoid a couple of the points along the way.
Aim to intersect the ridge just east of the steep East face to minimize elevation gain/loss. This final face borders on easy class 3 for 60 feet until reaching the summit.