Wedding Timeline

What are you going to do with your guests between the ceremony and the reception? There seems like an extra hour in there with nothing set for them? Unless I'm wrong with my math...

Along the lines of what Jacks said, it sounds like you’re having a Catholic gap, right? So are you planning on having your guests do their own thing in that time/provide their own transportation to the ceremony space? Or are you wanting some kind of entertainment or activity to keep them entertained during that time? If you’re leaving them to their own devices, which I know is more common in these post-mass receptions (hence the name lol), I would get all your portraits done during that time and then forego the cocktail hour. By then, your guests will have been waiting long enough, even if it’s a break. So I would start dinner service, toasts, dances, etc at 5 and then move on to the open dancing and festivities (if that’s what you’re planning) around 6:30/7 (depending on how many people you have and how long dinner service will take).

For your reference, our Catholic ceremony (processional to recessional) took about an hour and 20 minutes. That being said, we got married in a small church with a relatively short aisle (takes about a minute and a half to walk down if you're taking baby steps), and we had 14 couples in our processional (BMs/GM, parents, godparents, flower girl/ring bearer) plus the priests, deacon, and servers. We also included some extras in our ceremony, like placing of a cord and veil over us, exchange of coins, and bringing flowers to Mary and St. Joseph (who are on opposite sides of the church). Anyway, in general, I would estimate an hour and 15 minutes for a Catholic ceremony, because it's a regular mass plus the actual marriage part. Anyway, as far as a timeline goes:

2 - 3:15 PM ceremony
3:15-? Pictures/guests travel to reception venue
4:00 Guests arrive at reception venue - what do they do?
5:00 Cocktail hour starts
6:00 Grand entrance (if you like) or dinner starts, and then you do all the things you want during the reception. No right way to order them - it all depends on what's important to you.

The issue that PPs have mentioned is that your guests have nothing to do from 4-5 PM (or from 3:15-4:15 if they don't leave immediately after the ceremony). One option would be to move the reception up by an hour - cocktail hour starts at 4, grand entrance at 5, reception ends at 9. That would eliminate the hour in which they have nothing to do. If you want to keep the cocktail hour at 5, you could provide light refreshments (something super simple like water and cookies) for your guests after the ceremony ends if budget and space allow. That would give them something to do during that time.