My choice for most awesome Class I Bike Path in Ventura County is the La Conchita Bike Path that runs from Mobil Pier Road in Ventura (southwest of Mussel Shoals) to Rincon Point. The path is directly adjacent to the southbound Highway 101.
This distinct path premiered in September 2014 and provides for roughly 4 miles of unimpeded views of the Pacific Ocean on the west and is directly adjacent to the hustle and bustle of Highway 101 on the other side.
Class I bike paths are great to bring the entire family on as they are completely separate from street traffic. My kids love this path because it is flat, in great condition and is just so beautiful that its hard not to ride this path without a smile.
We brought the bikes to Rincon Beach Park to start our journey on the north end of the path. (Alternatively, park at Rincon Point or on Rincon Pt Road.) You first get to see surfers at the world famous Rincon Point, then on to the La Conchita Beach area.
There are several beach access points along the path. As part of this project, Caltrans built an undercrossing to enable folks to walk to the beach from La Conchita.
After La Conchita you reach a stopping point at the small community of Mussel Shoals, where you can stop at the Cliff House Inn for a drink and check out the man-made Rincon Island.
Walk your bikes across the offramp to the next bike path entry point, on to the next section of path that half circles southeast to its endpoint at Mobil Pier Road.
You will see beach area here referred to as Oil Piers Beach. There used to be piers here but they were taken down in 1998. There is parking on Mobil Pier Road for beach/bike path access; you can park here and ride the path the opposite direction.
Mobil Pier Road is the endpoint of this Class I path, but, you can continue south if you'd like by taking the Mobil Pier Road underpass below the 101 to Pacific Coast Highway going south, past Hobson Beach Park, Rincon Parkway, Faria Beach Park and so on. This section is not Class I path but I've taken my kids here and we enjoy it.
Great stuff! A Ventura County "Bucket List" item that all of you have to try!