It's 1852, and I am a young single man working for just below median income in a medium sized town in California. It is Friday night, and I want to blow off some steam. What recreational drugs could I feasibily lay my hands on? How much of my weekly wage will it cost me? If the sheriff finds out what I have, what is the likely punishment? Will others be interested in participating in the drug use?
To add - specifically - to the question you asked, by way of augmenting my previous comments provided so kindly by /u/knoperope:
In 1852 in the West, the focus wasn't on making substances illegal so much as making anti-social conduct on or off drugs punishable. The main thing you could lay your hands on - besides the full range of alcoholic beverages - would have been opiates. Many medicines employed this sort of thing, but you probably would not have used these for recreation. Smoking opium at a Chinese-run opium den would have been your most likely option as an alternative to beer and whiskey. But you probably will resort to beer and whiskey because that was the most accessible option. And you'll probably be arrested because I suspect you'll misbehave while drunk. I have no reason to suspect this last point other than the fact that you're asking the question, which leads me to conclude you are a very bad sort and you're looking for trouble. But like I said, using opium or booze won't get you arrested. Just try to behave yourself.
While you're waiting, take a look at these two comments by /u/itsallfolklore:
What kind of drugs where used in the old west ?
Were opium dens as common in the American Old West railroad towns as depicted in pop culture?
They don't answer all of your questions, but they're a good start.