Chili:
Couple of questions and comments.
1 - Do you prefer to stay on the Interstates?
2 - If you are driving straight through, when do you expect to leave and what time of the day/night do you expect to be driving through the central states?
I drove down I35 from Kansas City to Dallas last weekend and found it to be a long, boring, and uneventful trip. The roads are in good shape except for construction beyond where you are going to be turning off.
Personally I like smaller roads (as Lou about our drive back from Reno ;) ) and tend to choose the smallest possible road for the situation.
Last summer we drove up I35 to I135 and followed US81 north to I80 across Kansas on our way to southeastern Iowa for RAGBRAI. This proved to be very good roads and fairly well populated. Services might be a problem in the middle of the night but I doubt it. US81 parallels I29 on the west from Fargo south. The road does jog back and forth a bit (Interstates do as well to a lesser degree) and this might slow you down, but I have found you can often cut many miles off of trips by using these older routes.
That being said, US77 splits off of US75 just south of Sioux City and connects back with I35 just north of
It is about 120 miles from Sioux Falls to Lincoln (which is on I80),
about 130 miles from Lincoln to the intersection of US77 and I70,
and about 110 from there to the Freeway Entrance for I35 in El Dorado KS. This is a total of 368 miles.
From Sioux Falls to El Dorado via I29 and I35 it is 437 miles.
Interestingly enough, it is only 2 miles farther (370 miles) via US75 and I335, but there are tolls on I335 and I35 in Kansas. If you choose that route, I would follow I29 south to the Nebraska City Exit and jog over to catch US75. They aren't more than a mile or two apart at that point and it is pretty good bit south of Sioux Falls.
Also, don't drive into Stillwater as Cooperland is 15 minutes west of town. We will resurrect the instructions from I35 and 51.
Just some thoughts. Maybe XR3J will weigh in on this thread. He lives in Riverton Nebraska.