There was no reason for her to be in Colorado except thinking her hubby was still alive and here.
My guess is Edith left lots of little subtle clues around her house, letting hubby know where she was going.
Dean itched to ask her how she was so sure it wasn't Mr. David Dean who dropped her hubby into space but she began to sob anew, making any further conversation impossible.
All the more reason for hubby to stick around.
I haven't found an account of her death in the papers yet but her hubby died of the flu in '04 and it didn't mention his wife in his write up.