Well, there are two trains of thought here, neither of which lead to PP being a HC. He doesn't want that and will more than likely retire when KF does.
1) Hire inside what would probably be Woods or Wallace. Big bonus would be the continuity of the staff and recruiting but you are probably losing a HC and DC at the same time.
2) Hire a big name from outside. More risky but possibly a great upside.
Don't let people fool you, Iowa is a great job for a HC. Great fan support, great conference, money, facilities. The school has shown great loyalty to coaches. Drawback is not a ton of local talent but you are about 4 hours in every direction from a large recruiting areas- Chi, Min, KC, Oma, DSM, St L, Indy. I feel like distance for recruits is less and less of a factor as it was 20/30 years ago.