Either your first chance (if your you're heading east) or last chance (if you're heading west) to have a picnic in Saskatchewan, the Cummings Rest Area is just on the border between Saskatchewan and Alberta off of the Trans Canada highway.
The picnic area is somewhat treed for shade, and also offer the rare opportunity to have a picnic in the shadow of a huge sign that reads 'Saskatchewan'.
The picnic site has picnic tables and a portable washroom (which may or not be available in the future).