The Santa Monica Mountains are closest to Venice but probably aren’t the place to spend 3-days. Also, the PCT doesn’t touch the Santa Monica’s.
The San Gabriel Mountains have many backpacking options including the PCT. Not sure about the dog thing though, try calling Angeles National Forest headquarters 626-574-1613.
This web site - http://tchester.org/sgm/hikes.html - has maps and trail descriptions for the whole San Gabriel range.
Trips I might think worthy of spending 2 nights:
Icehouse Canyon to Timber, Thunder & Telegraph Peaks (could also include Mt. Baldy); East Fork San Gabriel River; Silver Moccasin Trail; Access PCT somewhere along Hwy2 and follow it to Mt. Baden Powell; High Desert Trail + PCT could make a cool loop exploring a diverse sample of the range.
Top Harrison Maps at – www.tomharrisonmaps.com – sells great maps of many Southern California backpacking areas. The trail maps titled “Angeles High Country” and “Angeles Front Country” cover all the hikes I mentioned as well as many more.
Feel free to email me - vainbigot@yahoo.com - if you have specific questions.
Carl
Carl