The Dawn Stone can be found in Route 3 and Route 18. As for Super Training, you can still get a Dawn Stone from Secret Super Training by defeating the Gallade balloon (These Long Shots Are No Long Shots!). You must get a Top Score though.
Source-Serebii Item Dex Dawn Stone
You can find a Dawn Stone on Route 3 and Route 18. (via Inverse Battle)
Hope I helped. :)