It only looks like trespassing because this area (8200 East Bush Lake Road) used to be a private residence. It used to have mailboxes out front, "PRIVATE DRIVE" and "PRIVATE PROPERTY" signs, etc., but most of those have been removed. It was purchased by the city in January 2005, and they haven't decided what to do with it yet. It's up on a hill, and has great views, so there have been discussions about turning it into a picnic area. But for now, it's just a vacant house. (Update: the house is gone.)
I contacted Randy Quale, Manager of Parks and Recreation for the City of Bloomington, and he gave me permission to put a cache up there. Anyone may hike or bike up there, but motor vehicles are not allowed.
Closest parking I could find is at N44 51.041 W93 21.809. Or you could park at the bottom of the driveway, but I'm not sure if that's allowed.
I used to have a cache here called Isn't This Trespassing? but that was muggled.
15Tango posted some interesting info about this property.