In rec.boats.paddle Mike McCrea wrote:

I'm wondering about on-going Lewis & Clark re-enactments.

There must be a few taking place. Anyone know who is doing what where?

Solo route retracers? Big expeditions in recreations of period boats
and gear? Anything to follow along on-line?

Don't know anything about it myself, but have heard it happens,
and here's a website describing varous events, although perhaps
not the events you want:

http://lewisandclarktrail.com/eventsstate/discovery.htm