You might want to observe the schools websites...bend.k12.or.us, sisters.k12.or.us, redmond.k12.or.us There are IB programs available at some of the high schools, yet not all...you cannot go wrong, as there are excellent teachers in ALL public districts you mention...Pilot Butte Middle School is starting an IB program, Cascade Middle School has one....Sisters community is highly supportive of the Arts...depends on your interests in urban or rural living and the plusses and minuses of each. ie; transportation time for you and your child. Hope that helps!
One more good website with links to all the schools is http://www.hdesd.org,
the website of the High Desert Educational Service District