Is your out and back to the Lake on Conn Valley?
After Pope Valley, we normally take White Cottage to Deer Park. So, you're taking Howell Mtn right at the top from Angwin? I don't know that I've ever been in Angwin proper. Any water and elephants in Angwin so we wouldn't have to stop in Pope Valley? I wonder if anything is open on Sundays.
The Krebs map shows a picnic area and restrooms at the southeast corner of the Lake which I think I remember. There is no icon for water. If we take Howell Mtn we could have no water all the way from Pope Valley to Moskowite Corner. Maybe we could find something on the Silverado Trail between Howell and 128, or just go into St. Helena.