With regard to southwestern Ontario, the Windsor area has WRCJ during the day. Some areas may also be able to pick up 91.3 WGTE out of Toledo, Ohio (outside of NPR news blocks) - particularly since Windsor's CJAM switched from 91.5 to 99.1. Some along the Lake Erie shoreline may also be able to get Cleveland's 104.9 WCLV from across the lake.
Sault Ste. Marie gets Central Michigan University's CMU Public Radio on 98.3 WCMZ out of Sault, Michigan, but they are classical only during certain daytime dayparts. The last time I was up there I was able to get Interlochen Center for the Arts' WIAB 88.5 out of Mackinaw City which is almost all classical but the Premiere Chaine station on 88.1 likely wipes out reception on all but the best radios.
I believe some in the Thunder Bay area may be able to get MPR Classical on WGGL 91.1 from Houghton, MI, across the lake. I thought I remembered reading somewhere that WGGL was at one time carried on the Thunder Bay cable system.