Having just moved from SW CO last year, I am partial to our OTC units (72,73,74,75,751). I lived there for 6 years and killed an elk every year (biggest bull was just over 300", and even the "bonus" kitty in my avatar). Wherever you decide to go, get to know the unit you hunt, scout, get off the main roads, and the best advise of all; get to know the locals! I can't tell you how many out-of-staters I would see chasing after elk that were long gone out from the area, not to be seen again until spring.
Now Iowa hunting, this perplexes me! Most definitely not working out to be everything I have heard it was! Deer numbers seem horribly low. Don't get me wrong, I'm ok with working my butt off to hunt a big buck, but going all season without seeing anything close to a shooter bites. I have never hunted this hard to be so unsuccessful.