Launch is $15 a day. I paid for a tent spot so I'm not sure how much the rv spots are. Couldn't be much more than $40 a day. Check the website out.
The best place to find information about Keller ferry is at the Washington state parks website at: https://parks.state.wa.us/714/Keller-Ferry-Marina All the rest of the answers are just I thinks!
Best to call the office. They are very helpful. Look at the possibility to Moore your boat. I think it costs $10 day if camping. Really convenient.
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