The lake we live on (Rainy) is 60% in Canada and we're over there all the time. We get the CANPASS, which used to be called the Remote Area Border Crossing Permit (RABC). The form is available on line. You can fill it out, send it in to Canada Customs & Immigration, and once they check you out, assuming you are not a convicted felon, you'll get the crossing pass in the mail. Then you, and any immediate family members listed in your application, can cross into Canada by water at any time without checking in. As I recall the cost is about $25 US per permit.
Since US Immigration laws do not apply to US Citizens, re-entering the US is not a problem from Immigration's standpoint. US Customs is a different matter. Given the scrutiny that border crossings are receiving today, I'd advise carrying some sort of photo IDs with you. Talking directly with officials in your area might not be a bad idea either to see what they recommend.
I hope this helps.
Al