Bus Schedules for July, 11

My husband and I will be joining friends on their trawler on the Great Loop cruise as crew during their journey through the Trent-Severn Waterway. We will drive up from the US and leave our car in Trenton but need a way to get back from Midland. We have read that many Greyhound routes in Ontario are being discontinued. Is there a bus that will take us from Midland to Toronto and Toronto to Trenton without an overnight stay? How many options are there timewise? Hopeful Yankee (with Canadian Roots)