This trip will require at least one overnight stay along the trail. Some parties often take two. The Connel Creek horsepacker's cabin is located about two thirds of the way down the valley between the McGillivray col and the base of Whitecap. It is certainly rustic with just a tarp for a door, but it is sturdy and dry and more than serves its purpose as shelter from the elements. Out here it might as well be the Ritz! Other good tent camping spots include the McGillivray col itself or Piebiter Lake, located about halfway down the valley on the north side.
Directions:
The route to the base of Whitecap begins off of Kingdom Lake FSR south of Gold Bridge. This road is in decent 2wd condition but definitely easier with a 4x4. The trailhead is located on the left side of the road immediately after the bridge over Piebiter Creek.
The trail begins by following the very overgrown track of the long defunct Piebiter FSR. There is lots of slide alder early and a few more patches later on until the trail enters the more open forest higher up. Soon after this point is the junction with the horsepacker's trail to Connel Creek basin on the left. This trail should you choose to take it is very clear and well maintained for the first section through the forest until it exits onto the grassy hillside, where it becomes much less distinct. It continues crossing a couple of small streams and then contouring along the side of the steep slopes, gradually gaining elevation and eventually taking you directly to the McGillivray col and down into the Connel Creek basin. This trail is definitely the recommended route to the basin so long as your routefinding skills are up to snuff, though I can't stress this enough as there are certainly some sections where it could be easy to lose the trail.
If you choose not to take the horsepacker's trail and continue along the old FSR track instead, you will soon reach some wet, swampy terrain, bypassing the remnants of two old abandoned mining cabins. At some point prior to reaching the first cabin, you will want to cross over to the south side of Standard Creek, where there is a well defined and dry trail to follow for a ways, allowing you to at least avoid some of the swamp. When this trail ends, cross back over the creek and continue straight on through the swampy meadows (there are a few scattered sections of trail if you can find them) until you reach McGillivray Pass, at this point, look for the best line up the steep hillside and head straight up, aiming for somewhere in the vicinity of the McGillivray col reference point. Upon reaching the col, look to pick up the horsepacker's trail and follow it down into the basin.
The trail extends down into the basin for a fair distance, eventually crossing over to the south side of the creek and then continuing through a mixture of wooded and marshy terrain before reaching the horsepacker's cabin.
On to the mountain...
From the cabin, cross back over to the south side of the creek, contour along the hillside to avoid losing elevation and make your way toward the base of Whitecap's southwest slopes (crossing the north branch of Connel Creek along the way) and then simply head straight up. This will be the steepest part of the climb (and is the crux of the trip in my opinion). The grade lessens higher up as the terrain gradually changes from all grass, to a mixture of grass and rock and eventually all rock (scree). At this point you can take virtually any route you want up to the ridge crest. I recommend angling gradually in the direction of the false summit ahead on the ridge. From the base of the false summit, the route follows easy scree to the right of the ridge all the way to the top, at which point the true summit is just a short ramble away.
Best of luck!