I am planning a trip to Nepal for the purpose of trekking in the mountains. I want to do a week long walk, with a guide and porters (might as well do it proper). The problem is, there are so many guides advertising their services I can't possibly tell the difference between the good, the bad and the great. Can anyone recommend me a company or guide to go with? And is it better to book once I'm there in Kathmandu or to pre0-book. any advice or tips appreciated. Namaste!