kilimanjaro and mountain gorillas

hello everyone a couple of questions..me and a friend will be hiking kilimanjaro in mid october and shortly after will go to rwanda to see mountain gorillas..so far we have done research on "zara" tours to do kilimanjaro trek and "amahoro" to get gorilla permits and take us to see them. has anyone used these agencies on similar trips? would you recommend them? have other recommendations? we are backpackers and are obviously trying to do these excursions as inexpensive as possible..also, any recomendations on what route to take up to the summit of kili? like i said we'd like to do it as cheap as possible and so the quickest route is the cheapest..but due to altitude is it difficult getting to the top in such short time? we are both in good shape and expereinced hikers but not experienced with this type of altitude..thanks in advance, any recomendations will be greatly appreciated :) happy travels