It’s about 6 or 7 mi from the Colchuck Lake TH with about 5k gain. The way to Colchuck Lake is about 5 mi, but the you have to hike up Aasgard Pass (about 2k gain in one mile) before you get to the Core Zone. Most people stop at Colchuck Lake, but the effort to make to the Core is totally worth it and it makes Colchuck look meh (I’ve done the hike multiple times and hate the hike from Colchuck Lake to the TH since it’s not too scenic and takes forever on the way back). I think the road is closed for the winter now so you have time to get prepared for next year