Could you please post the link to the data?

Having the data in Access would be preferable, if only for the aggregate and function methods. The Excel count() method could produce misleading results if extreme care is not taken in your data access methods.

Two maps on a slide is do-able, but it depends more on the size of the geographic regions you are mapping. Labels and notes might begin to "pile-up" on eachother at larger scales.

-Paul