I live out in the middle of nowhere in southeast Kansas, and my favorite place to take my kids for photo shoots is a site called Kalida, which is just outside the town of Yates Center, off of Hwy 54. There used to be a city there in the 1800s, but all that's left are the gates (made of stone) and a cave with a limestone "castle" built around the front. You can access the gate area without needing to ask; if you want to do photos in front of the castle, you have to ask the people who own the property (their house is right by). It's a historic site, so they're used to occasional visitors. It's especially lovely in the spring, as there's a fence that gets covered with honeysuckle and little roses. There's also wide open wheat fields across from it in the summer.
The town of Yates Center has some great sandstone brick buildings that make a good backdrop for photos; you might get some curious stares or questions, but people are pretty friendly.
Uxie, Azelf, and Mesprit Gijinka