I have been to the Beech Grove TCA show, and while it is a nice show, with a lot of great guys to deal with, it's pretty small and probably not worth driving two hours unless you were picking up something specific that you knew was going to be there.
Also, there is a show at Manual High School that is primarily HO scale. I don't know if it's a TCA show and I have not been to that show, but here's a website link.
http://www.naptownrr.org/#!our-shows/c1mk