Answer:
I can run but not walk. Wherever I go, thought follows close behind. What am I?
A trail, a union, together tied. Come across me and you will find you cannot change the course I'm on. Without me you cannot travel on. What am I?
I have wheels and flies yet I am not an aircraft.
You may enter, but you may not come in. I have space, but no room, I have keys, but open no lock. What am I?
Though it be cold, I wear no clothes. The frost and snow I never fear. I value neither shoes nor hose and yet I wander far and near. What am I?
The answer I give is yes, but what I mean is no. What was the question?