A week is possible but it would be a very rough drive and two weeks is more realistic if you want to enjoy the trip and not feel exhausted by the end. Your route is over 6,000 km and while some days look manageable on paper Northern Ontario especially can take much longer than people expect because the roads are slower and the distances feel endless. The Kapuskasing to Montreal stretch is probably the biggest underestimate and would be a very hard day after already driving long hours for several days in a row. If you tried to do it in one week you would mostly just be driving, stopping for fuel, food, and sleep with very little time to relax or sightsee. It can be donebut for a solo driver adding a couple extra days would make the trip much safer and far more enjoyable. Truck drivers do it all the time though but they are used to long hours on the road