On my server the trade always leave from Jangan Southgate; DW southgate; constantinople west gate; samarkand south and east gates. You just need to watch when the trade begins to take it. They all go to hotan. The dw part it takes the longest way... I hope it helps
Yes, there are some days and specific hours the players come by. Usually at saturdays at fortress war event. Most players are from egypt and turkey so you need keep the timezone in mind.
