Route Advice: Best Road to Enter Beni Bolivia from Brazil?

The Global Discovery Expedition. Good afternoon from the UK. In August, (after the rainy season) I will be crossing with a vehicle into Bolivia at Guayaramerin. My route south to reach Trinidad, seems to have two road options. Can you please advise the best route for a 4x4 vehicle?

One route goes to Rurrenabaque from Riberalta, them east to Trinidad. It is a longer route.
The second option goes directly south through Santa Ana de Yacuma, but looks to be a smaller road (or track).

Which route do you recommend?

Which route do the busses from Trinidad to Riberaita use?

Thanks for any help you can give me. Regards, Peter Crichton

My e-mail address for a reply is peter.crichton1@btinternet.com