We did not do an
ABD but we did add on time in the
Amazon following our first trip to the Galapagos. I'm not sure I'd recommend staying on a river cruise instead of a lodge along the river as we did the latter, but
definitely recommend time in the Amazon if you can swing it, boat or no! You'll be doing the same activities either way; I just feel like we had more walks in and around the forest during our time than the itinerary allows, and also wandered the lodge and lake side in our "down" time since we were on land. We also had the flexibility to do more night walks if we wished (my husband did; I was full on spiders after the first one and stayed in).