It's good that you're thinking of 2019 now, but IMO, it's a bit too early to be looking for a ride share. Right now, focus more on saving money for the con. Also, since you're in Raleigh, as @Sky_Storm said, there's an Amtrak station. Unless you're going to be bringing a lot of luggage, that should be all you need.
Either way, try asking again closer to the con, like in May. There will be many people looking for and offiering rides by then.
Also, to be clear, I wouldn't be able to help; I'm from NY, not NC.
full disclosure: I am not BronyCon staff; just someone who's been to his first BronyCon in 2018. Just sharing from opinion and experience.