Got the topo maps out. If there was a route to mowich, it looks like it had to follow park trails. Either most of it was on the road, or it dropped down to the mowich river followed parts of the wonderland trail.
Topo map shows a "boundary" trail running north south, just inside west boundary of the park At the most north east corner of Evans, up next to the park, the boundary trail looks like it ducks out of the park and connects in with evans.
Maybe they followed this south to the park entrance, connected in with the Paul Peak trail, to the wonderland trail, to Mowich.