The best season
Spring and Autumn, from April to beg June and then September and October. These are the best seasons to visit especially the high altitudes locations. Summer can be very hot, but is the best time to visit the mountains.
Transportation
We strongly suggest CBT ( www.cbtkyrgyzstan.kg), they are reliable and part of your cost supports local communities. Moreover they help travelers overpass cultural barriers by putting them in direct contact with locals. They can provide guides, drivers and complete itineraries across the country, including horse rides, trekking and sleeping in local villages or yurts.
Passing the Chinese border
If you intend to cross the Chinese border via land pass, you must prepare in advance. You need a Chinese Visa and someone who can help with language. CBT took us to the Chinese border, then another agency was waiting for us on the other side to help with inconvenient (LINK) and drive us to Kashgar. On the Chinese side we used www.johncafe.net. We talked directly to Mr John and he was very prepared and professional.
Visa
To enter Kyrgyzstan you need a Visa that will allow you to stay for 30 or 60 days depending on the type requested. For some nationalities (Italian is one of those) you can request the Visa directly at Bishkek international airport at your arrival. If you plan to stay longer than 30 days, official might require and invitation letter. Anyway we strongly suggest to contact the embassy in your country.