What time should our ceremony start?

Our ceremony will be at 4:30, we are planning to have cocktail hour from 5-6, and then the reception starting at 6. We are getting married at the beach and our reception site is within walking distance. You want to have enough time, but not so much that your guests get "lost" on the way to the reception. Hope that helps! If your locations have an onsite coordinator I would check with him or her.

Have you discussed with your officiant how long the ceremony will take? An hour seems really long to me.

Our wedding starts at 2 pm and reception immediately afterwards until 7 pm

Our ceremony is at 11:00 a.m. And our reception venue is 20 minutes away from the church.

Reception starts at 12:30, giving guests around 35-40 minutes travel time.

I'd say try to avoid any gaps. If your reception is 30 minutes away, your guests really only need 30 minutes between the end of your ceremony and beginning of your reception. That way, they are greeted with stuff to do and enjoy as soon as they arrive. I'd say start your ceremony at 4:30.

Yeah I'd do earlier. No later than 5

No gaps. You need to start your ceremony at 4 p.m. at the earliest. I would say 4:30 even. Definitely no earlier than 4.

6pm