Trail is in great shape and easy to navigate but becomes less obvious above the tree line. We scrambled up to the hut in mid-October with increasing deeper snow (0" to 12" at the hut) as we gained elevation. Pretty slippery and really, not the best time to be there. I would imagine in dry weather, this approach would be pretty straightforward. Views from the hut are amazing, not to mention the view from the open outhouse perched metres from the cliff edge.
Quickest way - drive to Castle Junction west of Banff on the Trans-Canada Highway. Take the Castle Junction exit and proceed over the river to a stop sign. Turn left on the Bow Valley Parkway and drive west to the Castle Lookout trailhead. Get out and give 'er.
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