Hi there! You can see a list of NCPA events here:
Conferences are designed to provide regional events for teams within driving range of the host fields, which we rotate on a regular basis. All eligible college teams are welcome to play any AA (5-man) conference events regardless of their home state. California teams can play northeast events and Florida teams can play in California, although as you can imagine this isn't a frequent occurrence. The reason we permit teams to travel to events outside their conference is to encourage participation, and in cases of distributed dates, offer an alternative weekend to play and earn national seed points if they can't make it to a home conference event.
Class A (xball) is slightly different. Due to scheduling restrictions and feedback from team captains, we may limit Class A conferences to teams that sign up and pay at the start of the season rather than opening it to anyone that can make the drive the weekend of the event and pay a standalone fee.
To answer the underlying question - "Why should I play in my conference?" - the greatest motivation is your seeding for nationals and taking advantage of conservatively priced events. Competing in conference events can improve your rank going into nationals, and placing first overall in your Class A conference for the season grants you a guaranteed spot in the Class A playoffs. In the past, season Class A conference winners have been offered a choice between playing their Friday prelim games at nationals and advancing regardless of their record, or deciding not to play prelims at all and going straight to Saturday playoffs. This rewards competitive teams that honor their commitment to play in the league year round. Above all, playing the full season in your home conference offers you the opportunity to win the coveted triple crown - first place in your conference, first place at nationals, and first place overall.