There is very little bank access to the N Lewis

on the north Bank there is access right in town behind the concrete wall.. a few miles up the river at the Island boat launch.. at the golf course. The cedar creek hatchery and at the boat ramp just below merwin dam

On the South bank there is access right at the bridge over the river in town, a few miles up there is a plunking spot along the road, then there is access at happa crusher and at the South side across from the Cedar creeh hatchery.
Anywhere around the hatchery will be a zoo and you'll want to avoid that. Happa crusher is also likely to have a few boats and a few waders ( if it's even low enough to wade)

access in the other spots is on marginal water or water that is sled after sled free drifting.
your better off in my opinion learning the Kalama...