Buses and micros (three-quarter-size buses) from La Paz arrive either at the bus terminal (during peak travel times) or Plaza García Lanza. It’s a steep walk uphill to the plaza from the terminal, or you can hop in a taxi (B$5).
From the Villa Fátima area in La Paz, buses and micros leave for Coroico (B$25, 3½ hours) at least hourly from 7:30am to 8:30pm, more on weekends and holidays. En route they stop in Yolosita, a dusty crossroads where you can connect with buses heading north to Rurrenabaque (B$100, 12 to 13 hours) and further into the Bolivian Amazon.
For Chulumani, the quickest route is to backtrack to La Paz. Although the junction for the Chulumani road is at Unduavi, few passing micros have spare seats at this point.
The road to Caranavi was only open from 4pm to 6am at the time of writing. Buses from Coroico will take you there (and on to other Amazon destinations) for B$30, departing at 2pm, 3pm and 6pm.
Turbus Totaí runs comfortable taxi services to La Paz, leaving when full (B$25, two hours).