A nice 18+ mile out and back to Jameson Lake along the Matilija Divide Trail. A sustained 1500ft climb over 5 miles up to Upper Santa Ynez camp can be grueling if the temperature is high - bring ample water. Only water I saw on trail was in the valley on the Murietta Trail and just before Upper Santa Ynez camp. I camped on the upper shores of Lake Jameson - note there are no trespassing signs nearer the lake and swimming is prohibited (though very tempting!). This lake supplies potable water to downhill communities. This could be upgraded into a tougher loop by taking the Franklin Trail to the Divide Peak OHV Trail - but camel up before you make that turn because no water the whole way back. The heat got to me on this one so I kept it an out and back. If you have extra time check out the waterfall up North Fork Matilija Trail!