The grays are slightly larger than reds. Grays can climb trees and its nothing to see one resting on a limb quite a way up a tree.
We have both at the cabin but the reds tend to be more nocturnal. A red was in the yard every night an hour after sun set. Reds are more cabin shy while grays seem to be a lot more inquisitive and have no problem coming right up to the deck.
I saw a wolf on the road on my way in to fish on Saturday morning, only a couple hundred yards from the driveway. He didn’t hang around long. Its amazing how fast they are given their size.