Most places will have minority tribes within the majority tribes. Nobility will be forced to pick families within the majority tribe though.
Beyond this it's entirely possible to travel and move from one location to another. Many plan to do this as the expertise of foreign tribes will be sought after in other locations. However, it must be said that this could prove to be a pretty harsh and long journey (it can take you real life days to go the entire way from the north to the south), especially since the road infrastructure won't be the greatest in the beginning.
And even if your OPC might be able to do some of the traveling while you're offline, you will probably have to be extra careful that the provisions remains stocked up along the way. Regional maps that cover larger areas of land will probably also be in limited supply in the beginning (assuming you're able to afford it at all).
Wards of the state might not be tribe or location bound though, so that might be a valid way of starting out with a specific tribe near a friend. Though a ward of the state is probably going to be more limited in regards to skills and knowledges. i.e. A Hrothi ward probably won't start out with basic knowledge and skill in Hrothi underground engineering or metallurgy like a Hrothi born into a NPC family with specifically that kinda expertise.
