SoCalHikes
4-5 days
Trans-Catalina (oh wow) https://socalhiker.net/hiking-trans-catalina-trail/ Catalina express is ~$37 per way, or ~80 round trip.
1-2 days
Mt San Jacinto (snowy in winter, but mild by March) https://socalhiker.net/hiking-mt-san-jacinto-via-marion-mountain-trail/ http://www.mtsanjacinto.info/viewforum.php?f=1&sid=eafb14fc05f8e1ed46604ec85ce7b068