How many college visits per day depends on the proximity of the colleges to each other, how much time you have, how much money you want to spend, etc….
With both my kids, we visited usually two a day, sometimes as many as three. That involved being on campuses for first and last tours of the day. Once my son and I saw four campuses in a day. My son ended up at the last college we saw that day.
In contrast, my daughter and I drove five hours each way in a single day to visit one college. She did the tour with no students on campus and that’s the school she ended up at. Both scenarios clearly worked out.
Our goal on longer college trips was usually to do something else besides see a college, especially bearing in mind that there can only be one in the end. No doubt that these trips are fun, but I personally think that in the LA area there are too many other interesting things to see. I’d aim to minimize time spent on campuses.