In all seriousness, it all depends on the year and the weather. By second season their usually isn't much snow so the elk will be fairly high. However they'll also move away from the hunting pressure and this will affect their elevation as well. I'm sure this isn't what you want to hear, but it all depends on the specific area your hunting. If I were you I'd start high and glass and slowly move my way down if you're not seeing any elk or fresh sign.
I agree with Woodmanduck start off as high as possible get above the elk and work down or wait until they are pushed up to you. Also if you are new to the area I'm sure you will see a ton of people that know the area and it won't take you long to see how they hunt the area and what elevations they start at. Now if there is a ton of people high and a ton of people low I would start in the middle elevations to get away from the crowds and hope the elk are pushed your way.
As others have said, the elk are where they are. My experience with elk movment 2nd season is that it is hunting pressure driven rather than weather. Mid October in CO can be 80 degrees at 9000ft or 0 degrees and under 3 feet of snow at the same elevation (most likely somewhere in between but toward the hot and dry side). If you know the area well and where people are going to be hunting, get into escape routes which may be up in elevation but may also be down. The tops of mountains are typicall public while the bottoms are generally private. The answer may be counter intuitive and you may find elk down low despite the heat simply due to pressure. Like wise you may find them above treeline avoiding heat and lazy hunters. Not a helpful answer but atleast it is one.
I agree that pressure from hunters is the biggest factor. It takes a big snowfall to get elk to move out of where they want to be. That can certainly happen in the 2nd season, but I would generally be more concerned with pressure. I have also seen large herds move to lower elevation after a big snow, then have hunter pressure and a return to warm weather push them right back up where they came from. There is no simple answer, just be mobile and try to react to what you observe. Good luck.
Every year many hunters and outdoorsman and women come out west from the midwest and east coast to hunt the prized mulies and elk. One topic that comes up often is altitude sickness. My advice for flatlanders is to get into the best possible shape. Start months before your hunt, usually really ramping up my cardio around March or April.
I run 5-10 miles 3 times a week, and also go for walks carrying my pack with about 50lbs to simulate what could be on my back. Another useful tip is to drink A...