I'm far from any sort of an elk expert, but I try to pick a camp about a half mile away or so of where I anticipate hunting in the morning, as well as a good vantage point to go into a few different basins if I luck out and have to hear them screaming all night. Elk are so nomadic, so listening late at night and well before sunrise can be very beneficial. Be mindful of not camping in a saddle which elk like to cross (I see this every single year and I drives me nuts). From my experience, elk can sometimes be pretty tolerable of human presence within a certain distance but they will not tolerate your smell. Know the prevailing wind, and always, always monitor the thermals. The take away here is don't camp where elk want to be, or between where they want to go.