I haven't been riding much over the past 3 years and starting in April I hope to change that.
My initial thought is to camp at Keyesville recreation area for a couple days. There is open camping there and vault toilets. We can ride the Kern canyon trail to Badger Gap and back. That's mostly a loop and about 50 miles of singletrack in a 52 mile ride. Second day is up into the pines and as high and far as the snow pack will let us go. By mid April it shouldn't be a problem getting just about everywhere.
Day 3 and 4 can played by ear. More fun from Keyesville or on the other side of the river in the Piute mts.
The days will be spent trail riding intermediate and better terrain. Getting deep into the single track is a great way to improve your overall riding skills.
I'm working on this past as I travel. Check back for more info after the next stop.