Property taxes in Florida are based on the current assessed value. They are adjusted every year.
In Florida, everyone is assessed the same - it doesn't matter if you are a citizen of another country.
However, if you are a fulltime Florida resident then you have the option of "Homesteading" the property.
The effect of this act is to decrease the taxable value of the property by $50,000.
ie if it is worth $300,000, it would be taxed as if it was worth $250,000.
In addition, if the valuation of the property went up quickly as it did between 2000 and 2006, the increased value for the purpose of taxation is limited to a specific amount - somewhere around 3%/yr, I believe.
However, on the other side if the property decreases in value by 40-60% as properties have in the past several years there is also a peg on the decrease.
In the States, if you pay taxes here, you can deduct the real estate taxes and interest paid on your mortgage off those taxes as a deduction even if the property is a second home to you. You cannot do this in Canada. Apparently they believe it is not good public policy to value property ownership over property rental. This is called public neutral taxation.
In the event you do not pay taxes in the US, you cannot take advantage of those expenses/deductions here.
Your property can be held by you personally or by a trust or by a corporation. You would need to consult your accountant to determine if you want to take the property as a business investment/rental property and then those expenses could be used as an offset against rental income.
Insurance costs are high for everyone. One of the facors they look at is the credit rating of the person owning the property and residing in the property. Another thing they look at is the number of claims that have been made against the property in the past - even if it was by the previous owner. They also look at any previous claims you may have made yourself on other properties. They also have higher costs for vacant properties. You might be able to discuss all of these things with your agent to get your costs decreased by providing an affidavit from your Canadian agent of you record up there..