How about a little local airspace lesson? This is the current sectional chart from our area.
The magenta "Fade" rings around the airports don't really indicate controlled airspace, they indicate the floor of the controlled Class E airspace above. Outside the OD of the ring the floor of the class E is 1200', inside the OD the floor is 700'. Since our upper limit is 400' we can legally fly inside those rings. If you do you need to be aware of airport traffic patterns and likely active runways and pay attention to aircraft activity.
If you look at Benton Harbor airport, it has a dashed magenta circle around it. This is class E "Surface based" controlled airspace, and you can't fly inside here without contacting ATC for permission/clearance. The same holds true for the dashed magenta Class E surface based approach/departure extensions you see north and south of Kalamazoo's airspace. (They're a little hard to see because of the information density) You'll also see that the dashed circle around Kalamazoo is blue. This indicates that it's Class D and you definitely can't fly in that area without contacting ATC. The grey rings around Kalamazoo indicate it's TRSA (terminal radar service area). It's shaped like an upside down wedding cake and because of it's altitude floors has no effect on our flying.
Essentially, we can fly in "Uncontrolled" (by the FAA/ATC) airspace minus any other restrictions like national/state parks, sports arenas, etc. The trick is to know which airspace is controlled. Class E is controlled airspace above 700' or 1200' depending on the magenta fade ring and to the surface in some cases as indicated.
Hope this helps. Critique, disagreement, and questions gladly accepted.