Hi Maddie,
Getting the right DJ, photographer, etc. without benefit of a personal meeting is a challenge.
Hopefully your friends on the right coast will be willing to help you out. They will have to serve as your ears and eyes while you are not there. If your friends are willing to do some of the legwork and meet with some vendors, that would be a major advantage for you.
Your friends may know someone who has recently married that can provide you with referrals. One of your first tasks will be to book your location. Find out who they recommend. Speak to the potential vendors by phone. Ask them for recommendations for your other needed services.
Once you have narrowed down the list of potential vendors, try to arrange a meeting between them and your representatives. Check out the vendors' website and ask the vendor what other wedding professionals and locations refer them. This will give you a good sense of their reputation and stature in the industry.
Here's a bit about hiring a DJ that you may find useful:
How To Hire A Good DJ
Good luck and let us know how it goes!
Craig