It would be a good idea for you to become a House Rabbit Society volunteer and network with them.
I have started a rescue before (rabbit) and helped with 2 different rabbit rescues as well and was also a board member with them. Best to get some experience under your belt to see what is truly involved – you need a board of directors – fill out state paperwork and then eventually you can become a 501c…not sure what is currently involved in the 501c paperwork – we filled ours out over 15 years ago and got approved.
Get a good CPA as your board member if you can – the expenses and donations and all that money stuff – very important….
I have to say that there are already many rescues in California and it would be wise to volunteer with them and learn all you can.
I know your heart is in the right place but you need alot of money – all my initial costs (vet care, spay/neuter, housing, food, etc….100% out of pocket).