Change of venue

I would contact them all asap and let them know. Maybe even resend another invite or email or something so they can get the appropriate info sooner than later. That way if they need to, they can change their RSVP

I would be sending out cards, emails, texts and calls. With a note of “We are sorry to inform you the venue has changed, but all else remains the same!”
The time difference can make this very hard for some, especially if hotels were booked close to original venue.
Was this the venues mess up? If so I might even look into legal action, but then again I am marrying an attorney lol!

Call, text, email, send post cards. If it was the venues fault I'd ask for compensation on the invitation costs.

Hey Kimberly!! I'm so sorry that this has happened!

The most important thing to do is let your guests know as soon as possible. You may want to send out new invitations, highlighting the change in venue and offering information such directions, parking info and nearby accommodations in case people want to stay the night.

In the meantime, it may be a good idea to reach out to your guests personally to let them know ASAP about the chance so that they are aware. Perhaps you could ask your parents or future parents-in-law to help out by also reaching out to guests.