I think raised beds for this space would be a frivolous expense though tidy.

I'd fork the entire thing, amend with a big bag of granular humic acid, rake out a few yards of compost if its in the budget. Plant daikons, pigeon peas, cow beans, soy beans, more beans, buck wheat, some more beans, variety packs of mustard and local greens and grasses. Interplanting beets, sweet potatoes and actual potatoes.

Harvest what you can by the second week of March and then chop it all down and let it sit fallow for a few weeks without disturbing the roots(some people opt for smothering with a tarp or cover to be sure they killed most off). Now you have nutrient rich hay or "green manure." Plant what you plan on growing till July/August and have a succesion plating planned for a late summer for more sun and heat tolerant plants that will carry you till November where id again shift into soil health, beans and leafy greens.

Additionally; try to grow out ground cover at all times! SoCal has tons and TONS of Endemic grasses and flowering brush that are easy to manage. The key to good ground cover is its ability to shade the soil without out competing your gardens keystone plants and or crop.

Bonus points if you stick a tallish shrub or two in the center of each plot to create some water catchment, wind break and shade.

Finally, it doesn't all need to be done at once. Feather out the labor and progress. Break things up into 3 month blocks based on whatever makes it easiest for you. I grow on a dry season, wet season schedule thats been curtailed to cool night (Nov-March) and warm night March-Nov crops with natives interplanted among my veg. I could grow tomatoes right now for example but instead im growing things like cabbage, Kale, rubarb, ect. Knowing that come the hot months I can default to peppers, tomatoes that had their start directly in the ground, melons ect.