We want as a one day trip without a guide. The only thing to keep in mind is to keep right in the middle part of the trek.
Trek is nice and falls are spectacular. Definitely a must in Chapada de Diamantina.
It's possible as a one day trip from Lencois even without guide:
Get the 5 am bus to Palmeiras (10 R$). Arriving take the van to Vale de Capao (15R$). Tell the driver to get off at the trailhead. Walk 200m uphill to trailhead, here wait for the parkoffice to open at 8 am.
The trek should take no more than 6 hours all together, including time at the waterfall.
Getting back you can catch a van from Villa de Capao which is 20 min walk downhill. This will take you back the Palmeiras and from there to Lencois. Bus back will be at 11pm. So use time to chill in Capao.
Alternatively you can try to hitch a ride or ask around.
The easy option is to ask tours coming back is they can take you to Lencois. Bargain for price, but maximum should be 50R$.
This way you can make the trip on 50-75R$ one day from Lencois, easy half the price of a guide.More