Hotmaps premium would probably have alittle better detail then the gold card for the kawartha's.
You may want to look into the Plus card. It would be alittle less money and you can load different areas onto the card up to 2GB. The big advantage of the plus card is that you will get the "sonar Charts data" here are some screen grabs from my unit with the "sonar charts data" turned on and off. NOTE: You will turn on the sonar charts data by enabling "fish n chip" on your chart plotter.
Off
On
Here is the menu options on how to turn it on.
Scott