Hi Linda,
Atenas doesn’t have any cart or scooter rentals. It’s a very normal Tico town.
Tamarindo gets tourists so there are golf cart rentals – I think the Best Western Vista Villas has an agency on site: http://www.tamarindovistavillas.com/Tours-and-Activities/action-tours.html. For scooter rentals there are several places along the beach road that offer them.
As far as skeet shooting, I don’t of any places in particular, although there are some shooting ranges in and around San Jose, the capital. I did some looking around online and couldn’t find any skeet places.