Yes you can walk from MK to CR.
It goes by the path for CM's parking lot and above you is the monorail (partly).
It will take you about 15 minutes at a moderate pace.
When you get to the end of the path from MK to CR - you have
to cross a road. Yes, a road with cars. There is a traffic light.
Then once the road is crossed - you go through the CR parking lot
to the bottom floor entrance to the CR - where the buses pick up
CR guests to go to AK, MGM & DTD.
It is not a pretty walk - but the path is paved and lit.
I would not walk it by myself. Only do it in a group or
with your family. I would not recommend the MK to CR
path for a wheel-chair bound person or with a stroller.
The path is not like walking around the Poly, GF or POFQ.
After MK fireworks - it is still the fast way back to CR.
Other guests will also be walking it too.
But not too many. Do not do the MK - CR path
too late at night. It will be desolate.
WDW is for the most part safe - but be aware of possible
harm if you place yourself at risk.
Just our thoughts. Better to be on the safe side.
