You can try Length of the Lake which is hosted by the Penticton Outrigger Club. 100 kms (not 100 miles), 5 legs...You need to meet the pre-determined check-in times for each leg of the race to be able to continue onto the next leg.
I think they have it planned for the weekend of Sept 18th this year. If you have never been to Penticton, it's a great town to visit with a lot of nice wineries in the vicinity!
http://www.pentictonoutrigger.com/