Drive to Durango and follow signs to the Durango and Silverton Narrow Gauge Railroad. It's near McDonald's and has a large parking area nearby. Buy a ticket for the train that stops at Needleton and ride the train 2.5 hours (~30 miles) to the Needleton stop. The train will drop you off next to a suspension bridge that crosses the Animas River. From here, it's a 6 mile hike to reach Chicago Basin. Note: you can also take the train from Silverton and be dropped off at Needleton.
To reach Chicago Basin, use the Approach Page. From your camp in Chicago Basin, hike northeast toward the end of the basin on the great trail - Photo #1. Near 11,200', turn left toward Twin Lakes at a signed junction - Photo #2. This trail is used to reach Windom, Sunlight, and Eolus. Continue up through the trees and past some rock slabs - Photo #3. Near 11,400', leave the trees where you have a great view of the two streams that flow down from the Twin Lakes area - Photo #4. Follow the trail north up the slope and cross the first stream at 11,700' - Photo #5. Immediately after the crossing, climb steep terrain for 300' before the trail angles right and the slope eases. Continue northeast to the second stream crossing, before 12,300' - Photo #6. Turn left and climb 200' to reach the top of the slope, near the south end of Twin Lakes (~12,500').
Your next goal is to hike around the first lake and continue east. If there is a lot of snow in the area, the easiest way to do this may be to hike around the left (west) side of the first lake and turn right to cross east between the two lakes. When there isn't too much snow, follow the trail around the lake (Photo #7) and up through the rocks. Photo #8 looks back on the area and also shows the crossing between the lakes if you came from that area. At 12,600', reach the base of a headwall that separates you from the upper basin. Water is usually running down the center - Photo #9. Follow cairns and trail segments up the right side and reach the upper basin near 13,000' where there's a great view of the route to 13,800' - Photo #10. In early summer, there may be a lot of snow in the area.
Continue east for a bit, then angle left and hike northeast toward talus and boilerplate rock below a gully separating Sunlight and "Sunlight Spire" - Photo #11. Continuing northeast up through talus, look for cairns that lead into the gully. Taken from Windom's West Ridge, Photo #12 is a great look at the gully. After reaching the dirt-filled gully, climb 400' east up to the left side of the gully. Near the saddle, turn left and climb into a notch on the left - Photo #13. The remaining route includes Class 3 climbing and a bit of route finding. Photo #14, Photo #15, and Photo #16 show the terrain as seen from Windom. Climb from the notch, traverse under some initial cliffs (Photo #17) and then scramble toward the ridge (seen in Photo #15) to a location where you may find a hole in the ridge - Photo #18. You can pass through this hole to reach the summit, but it involves more difficult ledge climbing on the east side of the ridge. Turn left and walk over to another section of steep rock - Photo #19. Look for cairns and/or the easiest way up and climb these rocks. Before reaching the top, swing left to enter a small chimney with a hole at the top - Photo #20. The hole has a large rock across the top. Climb up through the hole to reach ledges on the east side of the ridge. Turn left and walk up toward the final summit pitch - Photo #21.
The final summit pitch is very exposed but the rock is "grippy" when dry. The easiest way up is shown in Photo #22. Pick your line and gain the summit - Photo #23 and Photo #24. If you're comfortable with it and the rock is dry, the easiest way off the summit may be to jump from rock to rock. To climb Windom after Sunlight, angle left after descending the gully, traverse across rock and above ledges near 13,200' and then hike southwest up to Windom's West Ridge. Photo #25, Photo #26, and Photo #27 were taken along the traverse.
There are many dispersed camp sites between 10,800' and 11,100' in Chicago Basin. Some people set up a tent along the trail. The creek provides plenty of water for filtering. IMPORTANT: This route enters the Weminuche Wilderness area. Wilderness areas have special regulations and restrictions for party size, dispersed camping, campfires, etc. Also, dog owners should read the wilderness information carefully because some wilderness areas prohibit dogs to be off-leash and/or limit how close dogs can be to lakes and streams. If you have questions about the Wilderness area, please contact a U.S. Forest Service office for the National Forest(s) listed above.