Mt. Jefferson is the second highest mountain in Oregon, and a notch up in difficulty and commitment than the South side of Hood. The South Ridge is the easiest route, mostly a long ridge of class 3 scrambling. But do not underestimate this route. The last 200 vertical feet are kinda tricky! This route has a long fixed line traverse of an exposed 50+ degree snow field, (very loose scree/rock in late season) followed by a 4th class scramble to the single rock block of the summit. Long days and unexpected bivies are common on this peak. In a big group, 4 ropes and a lot of pickets are a good idea, 3 to fix the traverse and one for the summit block.
This is a limited use area, you will need a permit.