Don't know how far "up river" you want to go, but here are a few suggestions.
In Rio Vista, Duck Island RV Park or Sandy Beach County Park are nice. Both have plenty of riverfront. It's been awhile since we've been to both - and we don't fish - but either one or both may have a boat ramp, too.
Further north, there are riverfront parks in Oroville. We took our maiden voyage with our first MH to River Reflections RV Park in Oroville. Decent park and lots of fishermen there.
Hope this helps. Have a great trip!
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Fulltime since July 2009