It is shorter to go from Durango
to Kansas City (Missouri)
without doing the whole trip on I-70. If you go up to Denver to catch I-70 it will add time and distance.
The halfway point between Durango and Kansas City seems to be about at Kit Carson
and that's just before you get on I-70 and speed through the flat area of Kansas.
The driving time of each half is just about the same although the mileage of the second half of the trip is longer.
Kit Carson has a museum, a little park and a historic carousel (which may or may not be open when you get there). This area does not have much in the way of any kind of touristic attractions - kid friendly or not.