You can arrange, ahead of time, to bring your pistols into Canada with you. Check their Customs and Immigration and RCMP websites for information.
The pistols may have to conform to Canadian law, regarding their configuration. They will have to be in a secure, locked container that the Canadian border people can seal. Should you try to exit Canada with those seals broken, you would find yourself in very deep trouble.
The advantage to this scheme is that you needn't exit Canada by the same portal through which you entered.
There used to be a gun-and-hardware shop in Blaine, WA (right at the border), that would store your guns for you, for a stiff fee.
I don't remember the store name, but an inquiry to the Blaine Chamber of Commerce (via website) will tell you what you want to know.