Two things struck me when i visited Mabel Lake Provincial Park. One was how beautiful the scenery was, the other thing that stood out, unfortunately, is how inaccessible this park is. In their defense, this park is advertised as non-wheelchair accessible.
There are four pit toilets and to be able to get into them, you have to go up a concrete step, The roadways are not paved so the terrain is pretty rough with a few hills. With the unpaved roadways, the transition into the campsites is pretty flat. There is a path that intersects and runs through the entire park, but the terrain on the paths is pretty uneven and bumpy, so I would only try and travel it if you are in a group or have a freewheel wheelchair attachment.
In closing, I would just go to this park for the breathtaking beauty, and the idyllic scenery, But I would only camp there if you are in a large group of people who could help you