Along the same thoughts, the Canadian border agents have access to the United States Data bases. I have on several occasions been told, at the border that because I have a concealed weapons permit in Florida, that it is more likely that I have a gun with me when I enter Canada (I don't take a gun into Canada)
The border agents also have access to potential criminal records in the US, and if there is a DWI, felony arrest, many misdemeanors, you probably will be denied entry to Canada.
After 9/11 the United States and Canada have been sharing an increasing amount of information in the name of security, and as of 2010, the FBI criminal database is synced with the Canadian RCMP crime database.
If you have any RX drugs with you, have a copy of the prescription and keep it in the drug store original bottle. I ran into one customs agent in Prince Rupert who was going to go after my "Ship's Medicine chest" which should be immune from any restrictions of drugs as long as kept in the boat, under lock and key under international law. Fortunately he got a call on his radio to come to the ferry, and had to leave without inspecting it.
On the other hand I was in some serious trouble with US Customs last time I came back from Canada because I had some green onions Marie had purchased in Canada, and my chocks for the wheels were wood which might be suspect....
As far as bears--if you have bear spray, ( we ran into some places in Canada where it was required to have bear spray), be sure that it is approved in both Canada and the USA. (Our Counter Assault has both approvals on the canister). I had my .44 magnum shipped to a FFL dealer in Ketchikan. We bought ammo in Alaska, to avoid carrying it thru Canada, and raising suspicions. Shotgun was too bulky to carry in our RIB when we took dogs ashore. As Tom noted, hunting rifles and shotguns are fairly easy to take with you, but you have to follow the rules and have the permits ahead of time. Handguns--pretty much no go. When we checked into Canada, even by phone, we were often asked if we had guns aboard.
On the criminal issues: if you exclude a certain group of big cities in both Canada and the USA-- statistics on crime are going to be fairly similar.