You are correct in your opening statement: Where you live plays an enormous role in what you can and cannot do. You need be absolutely sure you are meeting all laws for your state. I am not a lawyer and not a resident of California, so I can't advise you there. This link may help you get started: http://www.californiahomeschool.net/howTo/legOpt.htm.
1. Figure out what courses would normally constitute a high school education in your state. (You can find this out by visiting your state Department of Education website.) List out those which you have already taken, those which you are currently taking, and those which you would still need to complete. Your homeschooling laws may or may not have specific course requirements, so be sure you are meeting those as well.
2. Design a plan of study to finish the courses you still need. Now here's where things can work quite well for what you want, but I would not be simply looking for the easy way out. Don't shortchange your own education! Think of your education as a complete body of knowledge that you want to master. Schools are designed for the efficiency of the schools, not the students. When you consider it, is it even logical to assume that every single subject from algebra to world history to chemistry can all be learned in the exact same amount of time and days? When you are freed from the constraints of a school schedule, it is certainly possible to master a subject in less time (or more time, if needed) then the academic school year mandates. You may find it takes you two months of studying two hours a day to finish a US history course, but five months of studying one hour a day to finish geometry. You can work your schedule to suit your needs, goals, and skills.
3. Find your materials for your studies. Although you are not looking at college per se, I recommend you explore the following sites that are designed to help students prepare for college-level testing and/or college credits. You can use the same materials for your studies, without taking the exams at the end.
a) Free CLEP Prep: http://www.free-clep-prep.com/
Choose an exam study guide based on subject, such as American Government, and then scroll down the page for a list of free and inexpensive study materials.
b) CLEP for Homeschoolers: http://clepprep.tripod.com/cleplessonplans/id4.html
This site gives basic lesson plans for each subject, generally broken down into a 9-week schedule. It does require the purchase of some books.
c) Homeschool College USA: http://www.homeschoolcollegeusa.com/
There are over 40 courses here, designed for homeschooling high school students who also want to take college-level exams. You can find all the core subjects, plus many electives. Everything is free and you do not need to purchase a thing. It is entirely self-directed and self-paced.
d) Saylor: http://www.saylor.org/
If you look at only one site in this list, make it this one. Between the general education courses, the electives, and all the courses offered under the various "majors," you could put together an excellent course of study to finish high school and you can work as quickly as you want to finish each subject. You can create a student account to keep track of your work and record the grades you earn on the final exams. This site is also free and does not require the purchase of any materials.
e) Carnegie-Mellon Univeristy's Open Learning Initiative: http://oli.cmu.edu/get-to-know-oli/learn-about-our-courses/
There's not a whole lot here, but what they do have is very good. Additionally, there are plenty of websites that list the numerous open-learning courses universities offer. Just do a search on "open learning" or "opencourseware." (Note, though, that outside of the Carnegie-Mellon courses, most open learning courses do require the purchase of a textbook.)
There are other options out there, such as the free online public schools, but for the most part, they do not let you move completely at your own pace.
I said it above, but I think it deserves repeating - don't shortchange yourself and rush through your education so quickly that you don't get anything at all out of it. Yes, frankly, you will forget a lot of it. Sometimes, though, it's not about remembering when the Spanish-American War broke out or how to find the area of a trapezoid. It's about training yourself to think. Like weight training will build up your muscles, "brain training" will help develop your critical thinking skills, something that can very much determine your success, or lack of, in life. I am not saying you can't finish school faster than average; many students would if they weren't locked into the traditional school calendar. I am simply cautioning you not to try to skimp too much, because there really is a genuine value to education, and you shouldn't miss out in your rush to finish.