By configuring a sales person's User Profile it is possible to give them access to their own appointment calendar/diary and nothing else. They will have as much access to account data as you permit, if you want to restrict the information they can see you can configure a special Panel View for the Account Details which only shows what you want them to see.
On the Account view screen they will have access to the button which opens Google Maps at the location of the appointment.
On their User Profile set:
Initial screen [Calendar]
Database Area
Owner
Status
Sales person
Default view [optional]
Authority level=8
To configure which fields are shown on the Calendar/diary go to the Menu option, Setup > Field Selection > Calendar