Long weekends are crazy like can't even hardly move for people busy and the trails are crazy busy. I've been out there working right down the road and normal weekends are busy but not too bad during the week you could have it to yourself.
Staging for chambers is on the side of highway 11 outside the chambers provincial park. You can also stage across the road on the access road to the group camp area. You can ride south down the trails to the river and eventually you'll have to cross the old rail line. Head west towards the pipeline and the railline is really easy to find.
Another staging area for the rail line is Horburg but the rail line is tricky to find and there is a lot of personal property there.
Best bet is to join a group ride with Hadster. He's a great tour guide and knows the area like the back of his hand...