Chiquitania
Often overlooked by tourists, Chiquitania has lots to offer if you are looking to get off the beaten track. The area is most known for its Jesuit churches, but we enjoyed the landscapes even more. The best way to get around is by car - if you do not have one then you may have to book a tour.
Nature
Culture
Amazon
Warm
Infos
How to get here
You will need a car to get around. This is prime road trip country. Otherwise you would have to move as part of a tour. Alternatively, there is a train (which we have never taken ourselves) that goes from Santa Cruz to the east into Brazil - it passes through Aguas Calientes and Chochís.
Things to do
Jesuit missions (north)
The region is most known for its Jesuit churches, which are located in the north-western part of the region. There is a bunch of them, and they can be visited one by one in one big loop. The full circuit take 3/4 days. Alternatively, you could just limit your visits to San Javier and Concepción and turn back to Santa Cruz from there.
Landscapes (south)
The second option would be to follow highway 4 going east. From San José de Chiquitos onwards the landscapes become quite fascinating. The best areas to visit are 1) Miradores del Valle de Tucavaca near San José de Chiquitos (for a 2 hour hike), 2) Chochís, 3) Aguas Calientes (a hot spring), and 4) Valle de la Luna/Mirador de Ñuflo de Chaves.
The two areas (north and south) could be combined in one big loop.
How it fits into your itinerary
At a bare minimum, you would need 2 days. However, spending 3 or more days would make more sense (depending on which areas you want to visit). You would start your trip from Santa Cruz and go back there. Alternatively, you could enter Brazil and visit the Pantanal area across the border.