(Spoilers Extended) A better reason for certain characters to go beyond the wall

A lot of people are complaining about how stupid Jon and danys plan is and at what a poor reason it is the writers came up with for them to go beyond the wall.

A better reason than going to get a wight would be if bran had a visions of the night king finding the horn of winter (a magical horn that can destroy the wall and them needing to stop the night king finding it. F

It would require a little exposition from bran but not only would it explain why the white walker army hasn't attacked the wall yet but it would be a good enough reason for them to go beyond the wall because if they don't find it first the wall would be destroyed.

Assume there is some landmark nearby in the vision so from the description tormund knows where to go beyond the wall. It was also make it believable that jon and co are close by to the night king in an area the size of canada