The Summit Trail from Pepperdine Trailhead to Patterson Lake is a 13 mile moderately trafficked out and back trail located near Alturas, CA that features a lake and is rated as moderate. The trail offers a number of activity options and is accessible from March until October. Dogs are also able to use this trail.
South Warner Wilderness is likely the least visited wilderness area in California. However, Modoc County law has less restrictions and protections for designated wilderness areas which hardly make this one "off the beaten path" if we take that phrase literally. The most glaring example of this is how cattle-grazing is permitted throughout the Warner Mountains. You may stumble upon cows resting along the trail and spook them, causing them to stampede in the opposite direction as I did. Their droppings will be obstacles to avoid on the trail, something one would expect while wandering out in farm fields and not in mountainous terrain at 7,000 feet or so. Keen observers are also bound to notice the more subtle ecological damage done by these grazing mammals - a large portion of native plant species have vanished here.
Despite these drawbacks, which are generally due to Modoc County not having the same wilderness value system as the rest of the state, South Warner Wilderness is worth a visit. The region resembles the Rocky Mountains of Colorado - with wide mountains that gradually rise, aspen and other deciduous trees, rich brown soil, etc. Volcanic formations and scattered remains of metamorphic rocks are also abundant.
Notes specific to this trail: Signs seem rare after the trailhead. Bring a map - unmarked trails intersect so avoid taking a wrong turn. If you are a novice hiker you won't have much obvious reference points other than lakes. Don't expect to see other hikers. I went on Labor Day weekend and saw no one.