Amtrak operates a train from Mount Shasta to Sacramento once daily. Tickets cost $40 - $110 and the journey takes 5 h 40 min. Alternatively, Siskiyou Transit operates a bus from Mount Shasta to Sacramento hourly. Tickets cost $1 - $3 and the journey takes 21 min. Greyhound USA also services this route once daily.
From Mount Shasta taxi to Dunsmuir Amtrak then train to Sacramento Amtrak. 5 h 50 min $109. From Shasta Base Camp bus to Weed then bus to Sacramento, CA. 7 h 20 min $52. From Shasta Base Camp bus to Weed, bus to Redding, CA, then Amtrak Thruway to Sacramento, CA. 7 h 45 min. From Mt. Shasta Shopping Center bus to Weed, bus to Redding Amtrak, then train to Sacramento Amtrak. 7 h 53 min $86. From Mount Shasta drive to Sacramento. 3 h 38 min $26.
No, there is no direct bus from Mount Shasta to Sacramento. However, there are services departing from Shasta Base Camp and arriving at Sacramento, CA via Weed. The journey, including transfers, takes approximately 7 h 20 min.