When you're getting your delivery schedule together, I think that it's a good idea to call ahead and check with the reception site to make sure they'll be ready for you.
It's no fun to arrive and find that the event ahead of yours is still finishing up. Or that they don't have the cake table ready. It can mess your schedule up and throw everything else off for the rest of the day.
When you call, though, don't necessarily believe the person who answers the phone. I've heard stories of people getting the okay from someone at the front desk to bring a cake early, then arriving and having nobody know what she's talking about.
You want to talk to the person who will be in charge the day that you're delivering, not the day that you call.
Here's the conversation that I had recently:
Me: Hi, I'm bringing a wedding cake tomorrow and I needed to know what the earliest I could bring it would be.
Lady at the desk: You can come whenever you want, someone is here at 8 in the morning.
Me: Will the room be set up that early, though?
LATD: I don't know anything about that. I don't know about the reception arrangements. Sometimes they set the room up the night before and sometimes they don't.
Me: Is there someone in the catering department who would know for sure?
LATD: Sure, let me transfer you to James.
Lady in the Kitchen: Hello?
Me: Hi, is this the catering department?
Me: Someone said that she was transferring me to James?
LITK: Yeah, just a minute.
Me: Hi, I'm delivering a wedding cake tomorrow, I needed to find out when I can bring it.
James: That's on you, I'm here at ten, so any time after that would be fine.
Me: So if I come at 1:00 that's good, everything will be set up?
James: Yeah, 1:00 is fine.
If I had taken the first lady's word for it, I could have been there at 8:00 in the morning, and I would have been waiting for two hours until James got there to set the room up. Make sure you're talking to the decision-maker, not just the random person who happens to answer the phone.