Jungle or Pampas Tours in Rurrenabaque?

Hi I am coming to Bolivia in September and am planning my trip as we speak. I would really like to visit the Amazon and a lot of trips are based out of Rurrenabaque but are expensive. Would you recommend a jungle trekking experience (3d2n) or a trip to the pampas??

Also can I get to Rurre from Copacbana?? Or do I have to go back go La Paz?? Is the bus journey as hellish as I have read about?? And if I fly there would I be missing out??

Thanks
Dan Kyte