1. Constant, steep rolling hills. I would rather do a long, more gradual or climb than a dozen steep ups and downs in a row.
2. Making sure I have access to an adult beverage after the day's ride. When I tour in PA, that can be a problem. Wine (my preference) and liquor are only sold in state run stores, which can be few and far between in the sticks. Beer is a little easier to find, but unlike many states, you cannot get it in convenience stores. It's so refreshing when I tour in places where you can buy a bottle of wine in the local grocery store, even in a small town.
3. For my tour of SD in June, I did not bring cooking gear. The challenge became finding carb-heavy meals. That was not possible some days and I felt somewhat like dirt the following days. I will probably never do anything over 3 days without cooking gear. I also like good coffee. Try to get that in a place like Edgemont, SD or Sula, MT.
4. Slowing down my mind, if you will. I am prone to worrying about ending the day late so I sometimes rush.