The Conejo Mountain Edison Road Trail (also referred to as the Powerline Trail) in Newbury Park runs adjacent to the Dos Vientos community (trailhead on Via Ricardo gets you to it) and takes you up about 1,000 feet in a few miles of hiking/running.
You'll be treated to beautiful views of the entire valley stretching towards Boney Mountain in the distance, then off towards Camarillo and the Oxnard Plain. In the video below, I ran to the top of the mountain; you can also run down the other side, all the way down to Old Conejo Road...but there's a locked gate there. However, the Ventura County Trails website provides some alternative routes that may come in handy at www.venturacountytrails.org/TrailMaps/DosVientos/AreaTrails.htm
That said, you don't have to go very far on this trail for great views of the Oxnard Plain.
The Powerline Trail trailhead is on Via Ricardo in Newbury Park, just west of Via Pisa. You can extend the hike by half a mile (each way) by parking at Dos Vientos Community Park and taking the Park View Trail to Via Ricardo, where you will cross the street (there's a crosswalk) to the Powerline/Edison Trail.
The Conejo Open Space Foundation has a simple map of the trail and additional comments at www.cosf.org/website/html/conejo-mountain.html