Cakewalk Sonar used to be very accessible, but the version of the program that was accessible is very old and almost impossible to find these days, and modern versions don't work at all.
Reaper, QWS and actually Sonar as well are digital audio workstations first, tools for scoring second, which I think is what the OP is looking for.
The Dancing Dots idea is a good one, it would also require JAWS which is pretty pricy though.
Sibelius seems like a good, not to mention affordable choice, as they have a knowledge base article on using the program with a free screen reader called NVDA. Would that work?
$1