Northfield is a tiny city along the interstate 35 corridor in Minnesota.
Contents
Hitchhiking out
North or South towards Minneapolis or Albert Lea
Exit 69 off 
is a heavily trafficed area outside of town. Here there is a Flying J truck stop. And both directions have large shoulders for cars to pull over.
Either direction hitchhiking is rather easy and shouldn't take too much time at the respective north and south on-ramps.
Hitchhiking in
Note: The town proper is 5 miles from the interstate. Ask your ride to leave you at the interstate.
Accommodation and Sleep
There are wooded areas around to camp in if necessary.