As a backup for a flat tire, I don't recommend an air compressor. Carry a "real" spare tire. However, if you are wanting to air down your tires to get more traction and
a way more comfortable ride when off the paved road, then, Yes, a compressor is great for when you want to air back up before getting back on the highway. The cheap air compressors that you plug into your cigarette lighter and advertise very high air pressure, are not useful. While they will fully inflate the tires you aired down, it will take hours to do so. The Viair compressors are very good quality compressors. Get one that connects directly to your battery via cables. I also really like the ARB compressors.
If you have not aired down your tires before going off road, you will not believe how much more comfortable they make the ride while you are off road. However, once you get back on the highway, driving at higher speeds with low tire pressure will result in really "mushy" and potentially dangerous handling, and really heat up the tires. The overheated tires will tend to destroy the tires via damage to the belts in the tire.
Also. When using the compressor, keep your engine running. Partly to keep from draining your battery, but also because the compressors work much better when running at 13-14+ volts when the alternator is charging the battery Vs. the 12+ volts when using only the battery.
And finally. If you have a compressor, you can frequently "plug" a hole in the tread or the sidewall with a tire plug kit. You use a tire plug, and then fill up the tire with the compressor. You may have a good spare tire, but the folks with you may not. A plug in the tread may be considered a permanent fix. A plug in the sidewall may get you back to the highway or home, but they are not considered a permanent fix. If you have to plug the sidewall, you will want to replace the tire ASAP.
And really finally. I am so jealous about you going to Canada for a fishing trip.
And one more thing. A good quality compressor will work well. But they generate a lot of heat in the air they compress. When this air cools off, the air pressure in your tire will be lower. So you generally want to fill the tires about 5 PSI above your normal pressure so that when the air cools, it will be closer to your normal pressure.