A few things:
Insurance, in some Provinces you have to have a $1,000,000 of Third Party Liability Coverage, not like some States were the only require the minimum. That is probably the only reason for the insurance.
Weapons;
Including "spring assisted knives" Switchblades are a NO NO, same as us entering the US, Knives must not exceed 9", blade and handle, however check as this may have changed.
GUNS
As some one mentioned earlier, NO WAY will you be allowed to carry/transport a handgun into Canada, no matter what Permits/Licences you have allowing you to do so in the US, concealed or open carry. Even Law Enforcement Types/Military/Secret Service may not be allowed to carry in Canada, Secret Service only if they are on Presidential Security Detail, Military only on Armed Forces Bases when working with Canadian Armed Forces personnel.
Of course if you come North to hunt you can bring in "Long Guns" rifles, shotguns with proper permitting in locked cases and thne you have to bring back with you to the US.
Prior arrests/conviction for DUI, Drug Possession and other what the Border Guards may consider serious offences, you can apply for paperwork prior to entry by going on the CBSA (Canadian Border Services Agency) website and filling out the proper paperwork to be allowed into the country, there is usually a fee for this, however, I do not know what it is. It is no different than a Canadian with a criminal record attempting to get into the US.
The above is not only for US Visitors, it is for all visitors.
geezerglide