I guess both sites of the Snow Light Path festival; the Canal and Former Temiya Railway Line must be crowded with people every day.
However, you can come across lovely creations to set off the candle lights in the back streets off the main sites.
Snow Light Path is the event involving whole city of Otaru, you can see candle-lit alleys even in residential areas.
Please try to walk back streets other than main sites. You can find some nice candle ornaments.