Unless you want to run an air conditioner at anchor, and in your climate you don't need to, then there is no compelling reason to have a genset.
I owned a new Mainship 34T from 2006 to 2010 and kept it in Long Beach. Our standard trip was over to Avalon or Two Harbors on Catalina Island where we took a mooring for 1, 2 or 3 nights. I never felt like I needed A/C. I had four GC batteries which would last for 3 days and stay above 50% charged.
So with 6 GC batteries, you can hang out for 4-5 days at anchor. If you want to hang out longer, install a couple of more batteries before worrying about the lack of a genset.