The Colorado Hunting Atlas is a great tool, to be sure, but also know that there are some elk at just about every elevation in this state that has grass, water, and seclusion. These elk can face less hunting pressure than their high country counter parts, and pressured animals in Colorado seem to be the new normal. A lot of the lower altitude elk reside on private property but some can be found on BLM and other parcels that allow hunting. Which unit are you planning to hunt?
Remember that even in the high country during archery season meat can spoil quickly if not properly cared for. This is especially true if you hunt at lower elevation. Keep this in mind if you get one on the ground. Good luck!