The flat, table-like summit of Morro São Jerônimo rises above the southern edge of the national park, affording spectacular 360-degree views of Chapada's rock formations, the Pantanal and the valleys below. It's an excellent and not particularly difficult day hike, though it is 18km round trip. Bring plenty of water and appropriate shoes.
You can opt to climb this as part of the two-day Travessia hike, which also includes the Circuito das Cachoeiras.
You must enter with a registered guide. Prices vary according to what you want; figure around R$200 per person. The webpage links to a list of guides.