I have virtually never used a travel agent. The last time I did it was to buy a Mercosur Pass (Latin American Air Pass) that is only avialable through agents - it took me 1 hour to explain to him what I wanted and how he could book it for me.
We manage without a travel agent. And it was great. You need maps, guides and a little bit of courage and crazyness. We prepare before the route with the internet help and it was sufficient. The rest was on the way.
Good luck!