I hunted Kansas mule deer back in 01,02,&03 with a muzzleloader. I drew the 1st year and purchased a landowner tag 2nd and 3rd hunt. I hunted the early season (around sept 15th). It is a very tough hunt as far as seeing deer. All the crops are still up and temperatures could be as high as 90 degrees. Your window of oppurtunity is generally 1/2 hour at daybreak and 1/2 hour at dusk. doesn't give you much time to get it done. I hunted unit 1 and unit 2. Both are good as well as unit 3. I definitley noticed the quality go down hill in the 3 years I was there. 01 was awesome, 02 was okay, 03 was terrible. There are some big bucks still living there but unless you live there you would need inside info to find out where they are. Also don't waste your time with walk in areas you need to hunt private ground. Get permission early or use an outfitter. There are not too many in unit 1 or 2.
Personally If I went back ,I would either try the late season (December, with a scope)or skip the muleys and go after a big whitail.