We meet in El Cajon at the garden/pond at The Magnolia (210 E Main St, El Cajon, CA 92020). It’s right at the corner of Sulzfeld and Main, across the street from the Downtown Cafe. Here are some pictures of the location on Google Maps — X marks the spot!
There is street parking available along Main St, though on popular days it does fill up. There are two parking lots nearby. I have marked both parking lots with a P on the map below. The red lines represent street parking.