Island Lake Recreation Area is a convenient, inexpensive, but utilitarian overnight stop at the Continental Divide, just west of Crowsnest Lake. It is particularly suited to larger recreational vehicles, with easy drive-in access to the campsites.
The least-attractive aspects must be its location below large limestone quarry, and its close proximity to the heavily used Crowsnest Line of the Canadian Pacific Railway.
In other words, stay here if it's late and you want daylight for the drive through the Rockies. Otherwise, there are better campgrounds nearby, notably Lundbreck Falls Provincial Recreation Area in Alberta, or Mount Fernie Provincial Park in B.C.