I commend you for your efforts to be responsible, and to ask questions long before you get the animal. Because so many people learn only about exotic herps, there absolutely should be an emphasis on native animals. Hognoses are also great because it is one of the better ways to demonstrate the differences between venomous and nonvenomous features and behaviors.
Many Easterns can be habituated to eat mice without any problems. Most of the problems in captivity I believe are associated with the heavy parasite load, so I recommend getting fecal tests one to two times a year. There are plenty of captive bred ones out there, you might want to consider traveling to a reptile expo, or better yet, get in contact with many of the breeders that advertise here on Kingsnake.com.
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...the oldest task in human history: to live on a piece of land without spoiling it."
Aldo Leopold (1938)
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
Calvin and Hobbes (Scientific Progress Goes 'Boink', 1991)