Avalanche Gulch is the standard route to climb Mt Shasta, typically done in spring/early summer as long as snow holds the loose rocks in place that pose a severe rock fall danger (helmets are essential here). Most people camp around 10000 feet at Lake Helen on Day 1 and summit the next morning. For a winter route climbing from Horse Camp via Casaval Ridge and descending via Avalanche Gulch see: komoot.com/tour/9090975