Flight
San Diego International (SAN) is the best option to fly into through all major airlines - just a quick 45 min to Vista (granted that's without traffic).
House Or Rental
There are lots of options for hotels and airbnb's in Vista if you want to be close to the venue. Feel free to expand your search to the surrounding areas, such as Oceanside, Carlsbad, or Encinitas if you want to be closer to the coast or try San Marcos or Escondido for a more inland experience.
Hotel
This is a great hotel located right off of Lake San Marcos. There are lots of fun activities, including boat rentals, golf, and a pool. Plus, it's only a 15 minute drive from the venue.