Carvers Café (open year-round, late May–late Sept. daily 8 a.m.–9 p.m., Oct.–late May daily 8 a.m.–4:30 p.m.; during early spring and fall, closing time varies from week to week) is located near the entrance to the monument grounds on the Lincoln side of the sculpture and provides the only dining facilities on-site.
It is a food court–style venue, with selections including hamburgers, pizza, pot roast, chicken, and pre-made salads. Entrées run about $8.50. In the high summer season, the café is busy, so it might be more relaxing to pack a picnic or enjoy lunch in either Keystone [1] or Hill City [2].
Memorial Team Ice Cream Shop (late May–late Sept. daily 11 a.m.–9 p.m., spring hours vary, closed in winter) is located in the same building as the Carvers Café, the first building on your right past the Information Center as you enter the memorial grounds. The ice cream is great and the gourmet coffee is well worth a small wait.
The Gift Shop (open year-round, summer hours daily 8 a.m.–10:30 p.m.; spring, fall, and winter hours vary) is located in the first building to your left after the Information Center at the entryway to the monument grounds. The shop is large and well stocked with every kind of branded item you could desire, including photos, t-shirts, sweatshirts, caps, books about the carving and the region, bells, spoons, sunscreen, and rain gear, among other items.
Links:
[1] http://www.moon.com/destinations/mt-rushmore-the-black-hills/mount-rushmore-and-the-central-hills/keystone
[2] http://www.moon.com/destinations/mt-rushmore-the-black-hills/mount-rushmore-and-the-central-hills/hill-city