I don't know the GMU you will be headed to but snow can be the major issue. In our case we hunt around the 9-11K foot level and always second season. Our location is about an hour north of the NM line so we are in south Colorado. We always get some snow and have often had a lot which limited our access to some good spots. Third season in our hunting area will definitely have lots of snow but if the area you are hunting is lower elk often leave the high peaks area to migrate to the lower levels. If your area is on the winter migration path then third season would be a better bet. If your grandfather hunts 3rd season that is probably why.