Quote Originally Posted by AndrewTall
Or have the wit to accept a local guide.
Aboslutly. Many of the "unforseen" problems in diplomacy can be avoided or prepared for if you have a local who will explain the lay of the land to you. I was looking over the contact list in the DMG II, and in general contacts need some adjustment for BR (different thread) but any sensible diplomat cultivates contacts in every court he visits. People who are out of power, out of favor, and whose policy choices differ with the current position of the throne, will all be eager to see outsiders come, for a chance to ride their coattails back into influence. Depending on their circumstances, the party would not want to publicly associate with them, but even so such people can explain the lay of the land from a highly interested perspective.

Over the long term, if you have genuine friends in court, they will act as contacts and allies in helping you through the difficulties of local issues such as minefields, personalities, and issues.

Good intelligence ought to proceed any visit to a court. Unless a court was established the day before yesterday, some good (if over-broad and dated) information should be avialable. When you get into town, or if you pass by important courts on the way, Gather some Information and attempt to get a sense of how things are working.