Hmm I see so you don't think it would be a good idea to ride it to North Bay from Toronto on an off peak hour? Have you had any major issues riding it everyday or has it be reliable? I'm just wondering if these bikes had any common issues or 30 year old bikes in general.
The run from T.O. to North Bay is what, 4 to 5 hours? Sorry, it's been over a decade since I did that run. I would expect that you will have to stop for fuel at least once. Probably twice if you are trying to go with traffic below Orillia. I get about 175 - 200 km from full to reserve. And reserve will do at least 50 km, probably 100 km, but I haven't pushed my luck that far. Also, keep in mind that there is a LOT of truck traffic until you are past Hwy 69 and you will get buffeted by them a lot. Our bikes are small and light after all.
As for problems on the road, the only 2 issues I've had on the road were electrical. The first was when my ignition switch decided to make crappy connections. The ignition would cut out and the bike would slow down very quickly. I was riding back roads and managed to get it home by wiggling the key or even turning it off and back on while coasting at speed. The second was when a connection from the voltage regulator decided it was corroded enough to get hot and then break. The bike began running worse and worse. It wasn't until I noticed my turn signals weren't working that I realized it was an electrical issue. When I put the bike in neutral, the LED bulb I had installed barely lit. The battery voltage was definitely below 10V! Again as luck would have it, I was close to home and was able to ride the rest of the way. The bike died in my driveway and wouldn't restart because the battery was drained.
So electrical issues are high on my list of potential failures. Bearings are another possible issue. If they have been serviced over the years, there shouldn't be any worries. If they have been ignored, well, that usually shows up hours into a long ride when the bearing overheats and fails. Or in my case, when the swing arm bearings disintegrated into powdered rust and the bike rode like a wet noodle. Without knowing the service history of a bike, it is best to assume the worst and have everything serviced before riding it any distance. Or you can just ride it and deal with what happens, when it happens (the CAA option). I commute on my bike, and ride to areas without cell phone coverage, so that isn't an option for me.
Keep in mind that our bikes are generally considered "learning" or "starter" bikes in North America. They were relatively inexpensive, light weight and easy to ride. The people who bought them were often first time riders and they often skipped maintenance. Especially after the 2nd or 3rd time they had dropped the bike and had to replace turn signals, mufflers, and pegs, again.
Then they sold it to another new rider and bought a bigger bike. And the cycle was repeated. It is rare to find a mature, experienced rider buying one of these bikes with the intention of riding it until the odometer rolled over. And maintaining it impeccably. Catching up on maintenance is the only way to be sure it was done and that the bike is as fit as possible.
Now, I'm NOT trying to be negative and I'm certainly NOT suggesting that our bikes are unworthy. I'm just trying to get you to understand that owning an older vehicle can be challenging. Some knowledge of things mechanical and electrical, and the willingness to learn, will go a long way towards making your bike enjoyable. And when the challenges occur, you will be able to think your way out of them. Carrying a spare set of spark plugs and fuses is a good idea, but only if you know how and why to change them. Having a flashlight so you can see what you are doing is forward thinking. Some electrical tape, wire ties, a spare master link for the chain, spare brake and turn signal bulbs, and some duct tape are all good additions to the factory tool kit.
Prepare for the worst and hope for the best and you will be just fine.