Depends on how much money and time you have. The distances you are planning to cover are great between San Diego and San Francisco, but definitely workable by car. If you are considering flights there are plenty connecting the 3 major cities you mentioned, but you'll miss out on a lot of cool stuff in between. There is also Amtrak rail, the Pacific Surfliner connects San Diego to LA to Oakland. If you fly or take rail you'll need to rent a car to get around each city. Might be more practical to just rent a car in LA and drive up and down the coast. Lots of scenic drives and breweries. And wineries.
NO. NO NO NO NO. do not take the train. it almost never makes sense in CA. and from LA to SF you start on a train, get off and get on a bus, and then back on a train. this happens out in the central valley in the middle of no where.
LA to san diego in car is like 1.5 to 2 hours. from SD to SF is like 10 hours, or 12-15 if you drive along the coast. from LA to SF is like 6-7 hours. none of these routes are faster on a train. or cheaper.
if you buy plane tickets in advance you can get from LA to SF for like $50-60 bucks, and likely the same from SD to SF, but LAX is bigger airport and has more flights available. so in theory, you could drive from LA to san diego, hit some orange county and north san diego breweries on the way. then hit san diego, even take a day and check out the breweries across the border in tijuana (i can give you a list if you like). from SD you fly up to SF, or go back to LA and then fly to SF.
there's also a super cheap busses that are like $10-30 to get from LA to SF. (megabus, boltbus) the ride is crappy but its cheap.
San Diego- definitely stop at white labs. you can do flights of the same beer recipe brewed with 3 or 4 different yeasts, very good education. stone, ballast point, st archer, mike hess
North San Diego/ orange county- lost winds is pretty good, bagby beer is decent, pizza port has few brewpub locations, and in orange county you can check out bootlegger, the bruery is overrated in my opinion but some people definitely love it.
LA- south bay- DEFINITELY check out Phantom Carriage- awesome sours. smog city is ok, monkish is good, golden road is so-so, highland park is a bit far from downtown/westside but has good stuff. yourkshire square makes modern english style beers, definitely worth a trip as i assume you dont get any of those in brazil.
SF area- hit russian river but be prepared to wait. lagunitas is awesome. fieldwork is decent. cellarmaker is decent. almanac is overrated, but food is good. drakes in oakland is good if you like west coast ipa. heretic has some decent beers too.
in short, there's a ton of breweries in all of these locations. plus tons of other bars, restaurants, etc. so to be honest, i'd make a list of the ones you "must visit" and then get opinions on other smaller breweries to visit from the folks you meet along the way.
or better yet, sample some local breweries at a beer bar, find the ones you like, and then go visit them when you're done with the "must see" breweries.