Mount Elwell, one of the most northern Sierra Peaks Section (SPS) peaks, resides on the border of Plumas and Sierra Counties in Plumas National Forest. Though the summit is tame by most standards, the summit provides an exceptional view of the Lakes Basin below it, as well as views of Sierra Buttes, Weber Peak, and the Bald Mountain Range/Sardine Peak to the South/SE; Mt. Lassen can also be seen to the NW on a clear day. If you can resist the temptation of jumping into Long Lake and exploring the islands that will tempt you from the summit, you could probably fold the hike in with Sierra Buttes the same day.
From the San Francisco Bay Area:
I-80 east, through Truckee
89 north through the town of Sattley
49 west (the road sign says "south")
Gold Lake Highway is the road that passes through the lakes basin, go north.
The trailhead of choice is at the end of an access road marked with a sign that says "Elwell Lodge"; turn of Gold Lake Highway here and stay on the main access road until you come to its end, which is a parking lot. There are campground signs along the way, ignore these and drive straight to the end of the road.
The Highway is apparently plowed in the wintertime, so a winter climb would not be a problem, but, I'm not sure if the access road is open. The trailhead is only about 0.6 miles from the highway so this wouldn't be a big addition.
Check here for Plumas NFS road closures: http://www.fs.fed.us/r5/plumas/conditions/roads/
None, no permit necessary for a day hike, no entrance fees, or parking permits.
There is camping available in the Lakes Basin. The Plumas NFS site has all the information you need about it:
Alternatively, you can contact Plumas National Forest directly:
Plumas National Forest
159 Lawrence Street
Quincy, CA 95971
Tel: (530) 283-2050
Long Lake Trail
From the parking lot at Elwell Lodge, take the "Silver Lake" Trail. This trail later forks, take the "Long Lake" fork. It will fork yet again, take the "Long Lake Trail", which is not on the Topo (see trailhead sign image)
This trail follows the east side of Long Lake and connects with the Trail that runs along the base of Elwell. When I hiked this Trail, there was a log blocking the beginning of it, apparently placed by the Forest Service. This trail is not damaged or difficult to follow; it may be difficult to follow in the winter though, so if you are doing it then, I suggest bringing a GPS because you cannot see the lake most of the time. Once you've crossed the dam, head NW until you connect with the summit trail; follow this trail to the summit.