A friend of mine asked me to come up with a summer vacation idea for her within 2-3 hours of San Diego where there would be a variety of activities for the kids, including some type of water play. Being in Southern California, the most obvious choice is to head to the beach. But I came up with a different option. There are plenty of things to do in Lake Arrowhead no matter what time of year to visit–so I suggested a fun family trip to the mountains. Lake Arrowhead is a charming mountain escape that’s family-friendly, packed with outdoor adventure, and within a few hours of Los Angeles and…