You might want to drive up to Polebridge along the North Fork....although maybe not all the way depending on time.
Maybe include the Camas Road on the way back...time it for "dark+-30min to an hour". Better animal movement att imo.
Nice time of year for a ride up there. Maybe see those elk that hang out just South of Polebridge on that private land...the parcel with miles of very expensive wood rail fence. I saw a VERY nice whitetail buck on that land around August 1st. He'll be a MONSTER buck by Sept 17th. He'd be a great sight if you got lucky. There's nice animals to be spotted in that area. They move back and forth across the river to and from the park.
And after dinner maybe ride up Big Mountain Rd to the ski resort. Great views of the Flathead from up there if the weather is nice....even if it's dark.
pocketlint