Weather is always an important consideration when planning a trip to Pioneer Cabin. Weather in Sun Valley (elevation 6,000 or so) is relevant since the trailheads are just above that elevation. But the cabin itself is at a much higher elevation. More specifically, the point forecast for Pioneer Cabin from NOAA is available here. There may also be recent beta about trail conditions on the facebook page. The National Resources Conservation Service maintains a weather station in the vicinity at 7,620' elevation which can provide further trail information, including temperatures recorded and snow depth.
There are a number of routes to Pioneer Cabin and all have various advantages and disadvantages. Regardless of the trail one chooses, there are three main trailhead parking areas.
The blue waypoints on the map indicate the "three-season" parking locations before and after the roads have been cleared of snow. Trails can easily be seen by zooming in on the satellite base map (including the very crowded Corral Creek parking lot).
There are many websites with beta regarding these trails so current info is readily available. I placed a link below to alltrails.com feedback for each of the four three season hikes.
Three season routes
Corral Creek (Trail #122)
This is the traditional, original, and most popular trail to Pioneer Cabin. The trailhead sits at an elevation of just under 7,000' and the hike has a vertical ascent of around 2,500' over 3.6 miles. In the early years, an intermediate ski hut was built about the same time as the Cabin itself. This is the current trailhead. Sawmill Hut was built to provide a start point at the end of a snowcat or dog sled ride from Sun Valley to the trail's base. Most early trips to Pioneer Cabin made their way up this trail that includes about a dozen long but comfortable switchbacks through timber (lending shade) to aid in the elevation gain.
Within about a mile of the cabin, the trail intersects with the Johnstone Creek trail (see below). For much of the journey, Johnstone Peak's north face is well in view. The grand view of the Pioneer Range only appears as one crests the saddle and the cabin finally comes into view following another steep but manageable sequence of switchbacks. This route can be done in the winter (I've done it twice), but the approach is very, very long starting not far from the Sun Valley Lodge where Trail Creek Road is blocked for the winter.
Long Gulch (Trail #123)
One might choose this looooonnnngggg route into the cabin, or at least longer than Corral Creek (the shortest). The gulch is well-named and in my opinion the name is understated: it seems to go on forever. It is described by some as a marathon (my wife included, who is still unhappy with me for trying this path with her). Same trailhead as Corral Creek, but very different route. The views of Johnstone Peak are actually fairly stunning and the route includes passing by an alpine basin, but this is one you'd likely only want to do as part of a loop that includes the Corral Creek trail above. There is elevation lost which makes this vertical of over 3,000' with the total loop being 8.8 miles. (Some simple math puts the one-way up or down Long Gulch between cabin and trailhead to be 5.2 miles.)
North Fork Hyndman Creek (Trail #165)
This is another loop opportunity or out and back (I strongly recommend the loop). The loop would combine this route with the Johnstone Creek route (below), although the trailheads are a little over a mile and a half apart. If you do decide to do the loop, I recommend that this be the second rather than the first leg. The trail itself is a long and gentle hike along the North Fork of Hyndman Creek. It shares a trailhead (including a rest room) with the trails into Hyndman Basin and Hyndman Peak. It is a beautiful hike, but at the end is a very steep switchback challenge that leads from the valley floor to the cabin, gaining about 1,400 vertical feet in the final mile, hence my suggestion that this be done on the downhill. The one way distance is about 4.2 miles, with a trailhead elevation of 6,800' resulting in a total vertical gain of 2,700'.
Johnstone Creek (Trail #206)
The trail to Pioneer Cabin from the Johnstone Creek Trail is a short marathon, but there are some spectacular views of the western Pioneers about four miles in after reaching the headwall of the creek drainage. After about half a mile of that amazing view, the trail turns west and over a saddle to the Johnstone Peak side, effectively hiding the view to the east. Another mile or so brings one to the junction with the Corral Creek Trail #122 and shares the final mile to the cabin. As mentioned above and as time allows, I suggest that this be the first leg of a loop with North Fork Trail #165. The last mile and a half or so of the loop would be on the road connecting the two trailheads, or of course two vehicles could be utilized to shorten the total somewhat. This complete loop is 11.8 miles. One way would be 6.1 miles with about 2,800 feet of net elevation.
alltrails.com | Note that the trail beta varies here for the loop, but probably accounts for some "up and down" along the way for a total of over 3,000' of elevation gain.
Here is a photojournal of the North Fork-Johnstone Creek loop.
Button Creek Ridge (Todd Schwarz route, no trail)
The red waypoint marker on the map at top indicates the winter trailhead nearest the cabin which uses a route I've plotted up Button Creek, or rather on the ridgeline directly to the east of Button Creek. Some friends and I made this trek in March 2016 to watch the spring equinox full moon arrive over Hyndman Peak., and have utilized it since. The track itself is below. It utilizes a mile or so of the North Fork #165 trail, so there is a restroom facility on the route. Pay close attention to snow, weather and avalanche conditions on this route. It is not for those without significant winter mountaineering skills and gear.
The track is the route up and follows a ridge very closely for those on snowshoes (it's rugged and parts will require snowshoe removal. Skiers will want to switchback up to the ridgeline north of the timber. Coming down may vary depending on skiing conditions and other abilities. But from my unfortunate experiences, I strongly recommend avoiding the Button Creek canyon due to the heavy and dangerous deadfall. This is about a seven mile one way route with an elevation gain of 2,900' net, but the ups and downs on the ridgeline push it well over 3,100'.