Nice pictures! Actually a future client of mine gave me this link: I have a sustainable tourism company in Huaraz (www.respons.org) and I have included the "Three Civilizations Adventure" as a product we offer. It's funny: when I first did this route with some friends in 2004 (because we had read about Tantamayo in some magazine), I made the same mistake when I arrived to Huanuco Pampa to try and cross the river in the very place of this picture!! We fortunately made it through back and forth, but it needed several tries to climb out of the river again. Now I know the route to get there even without a 4x4 vehicle :-)
It's so nice to see that someone else did almost the same route, apparently years before! If ever anyone would like to take this route, too, you may send them through to us since we now have quite a good experience organizing this trip.
All the best, and best greetings from Huaraz!
Guido van Es