You nailed it! As far as cliques go, the two guilds I belong to have groups that hang out together, but it's ok to wander to a different group and socialize. One guild is small, and I enjoy that one because it's more relaxed, more a social outing where people do what they want while visiting.
The other group is larger, more goal oriented, offers classes and speakers and so on. It was overwhelming to walk in and not know anyone. But eventually I made friends and eased into the guild activities. As for the political stuff, just be nice to everyone and ignore the bs that some people thrive on. Much easier said than done, I know.