Guests arriving an hour early

Generally they arrive 30 minutes before and are seated t that time. Any longer than that they get antsy. Perhaps you can have lemonade and cheese and cracker platters for those waiting longer?

It's a bit early but not terrible. I went to a wedding last year that started 30 min late because of rain and I arrived 30 min early, so we ended up waiting an hour. If you do have guests waiting, I would HIGHLY recommend having some drinks available (water at a minimum, but tea, lemonade, or even a welcome champagne would be very nice) and some snacks too. Make sure there is somewhere guests can sit whether that is early access to the ceremony seating or a lounge-style set up. If it will be hot or cold try to plan accordingly with heaters/blankets or fans/access to an area with AC.

You mentioned no-one is looking at your website (same here girl) so another option for sharing that info would be to have weekend programs/itineraries made and given to everyone staying at the hotel when they check in. You can keep it cheap and just get a template off Etsy, or you can do small welcome bags and include the itinerary in there. Also, however you end up sharing the info, you will probably need to encourage some people to take that earlier shuttle, or they might all assume they can just wait for the later one and then they won't fit.

I don't think anyone will take the earlier time, which will cause an issue. Do you have specific people who will need the shuttle? If yes, I would talk to them ahead of time and book them on the shuttle. I would hate to arrive an hour before the wedding because you know they never start on time so I would be sitting around in uncomfortable chairs for minimum 1 hr.