Travel to Lewiston, CA is a bit of a trek due to it being in a rural part of Northern California.
Most people will likely need to drive depending on where they are coming from. You can also fly into Sacramento and rent a car from there.
There are options to fly into Redding directly through United. I would set flight alerts right away as they can be a little pricy.
Lodging:
A short drive to the venue and a great option! This location is on the river and would be a great option for a large group to stay together.
This is a great option for anyone ok with camping! They have RVs you can rent in addition to tent camping sites (or RV sites if you have an RV). This is actually walking distance to the venue and would be a great option if this is your thing!!
Note from Holly: Them having RVs to rent was news to me. This would be a very cool option if you are cool with it!
There are also airbnb locations around Lewiston which would be a great option.
Weaverville is a 20 minute drive from the venue and will have more accommodation options (in addition to stores and restaurants).