You would probably be fine without these words, but I'm going to post them anyway.
Sadly, I did not post this before the United Methodist Church General Conference. Sorry, Methodists.
A water bottle and travel mug
You will want to have a way to hydrate. Hydration is important for your stamina! I imagine that certain areas of the country frown more on bottled water purchases than others, so I find the best way to avoid any sticky ethical issues around plastic waste is to bring my own water bottle. The same goes for a travel mug. If you bring your own, you won't contribute to landfill waste the five times a day you get coffee or tea! Win-win!
(Update: commissioners and advisory delegates to the PC(USA) GA will be gifted a water bottle, but the rest of us have to fend for ourselves.)
You hydrate with water, but your skin wants hydration, too. Trust me. This is a gender-inclusive recommendation.
Layers (like a shawl or scarf or sweater for inside the convention hall/hotel)
I have yet to feel comfortable throughout an entire day in a convention center. I think it's a requirement that those places be too cold, and completely at odds with the temperature outside. If you're me, and you're sensitive to temperature changes, bring layers. I hear the Oregon Convention Center is cold. Added bonus: fashion statements.
Something for rain
If you are going somewhere with rain (hello, Portland), you should arrive prepared! Even if you're me and you don't melt in the rain, it might be nice to have something to cover your work clothes in the rain, like a hat, umbrella, or raincoat.
Casual clothes for "going out"
You will probably have your usual work clothes, but at some point, you're going to want to go out for a drink with friends at 11pm so you can debrief the day. Bring jeans, a t-shirt, a sweater, and sandals, or your personal equivalent.
A travel toothbrush? Mints? Gum? Whatever you need, make sure you bring it with you. I'm usually that person who forgets and then has to hunt around for something. Don't be me.
Bring enough. You never know what's going to happen. Will it be humid? Dry? Raining? Be prepared!
I have yet to spent all day in heels or thin flats in a convention center and thought, "wow, my feet feel great!" This goes for those of us running between rooms/sessions or working an exhibit hall in particular. It's worth everything to have a pair of shoes that pass for work-appropriate (depending on the kind of work you do) that are also comfortable. If you're going to Portland, you'll be walking a lot, and using public transportation, so be prepared! Worst case scenario: have a pair of cute shoes you can slip into your bag and switch out when you're up front presenting.
And that's a nice segue to...
The bag you will carry all day
It might be a backpack or a large tote or a murse. Whatever it is, it needs to hold your things so you don't go back and forth between the hotel and the convention center. It should be large enough to hold your computer (if you need it), and your hymnal (if you have one), along with your water bottle, phone charger, wallet, etc.
Cash in small bills
This is so you can tip. You should be tipping housekeeping at the hotel, bellhops, valets, etc. That's because our wage economy is messed up. Wouldn't it be nice if everyone's wages were a sufficient appreciation of their work? Yes. It would be nice. But that's not how it work in this country, so bring cash. If you bring larger bills, hotels can give you smaller change.
No convention center will ever satisfy your snacking needs. For those of us who don't often get the chance to eat a full meal because we are working the exhibit hall, it's especially important to bring a robust portfolio of snack options. Buy that stuff beforehand and bring it in your suitcase, or locate a grocery store near your hotel. I usually bring almonds and breakfast/protein bars. Those of us working the exhibit hall will often make a trip somewhere to pick up things we NEED, like sour gummy worms (obviously).
(Update: technically, we're not supposed to bring in outside food because contract details. So this is my official notice to you about that.)
Make sure you have a version of the Bible and the hymnal downloaded into your phone, especially if you are not a voting delegate. The PC(USA) voting and advisory delegates will receive a copy of the hymnal. The rest of us are on our own.
Do you love spending ten days living out of a suitcase in some anonymous hotel room? Okay, if you get tired of it, think about something small you can bring with you to make your hotel room less hotel-y and more home-y. A framed photo, a little travel candle (but be responsible with that!), a stuffed animal (I know people with a consistent buddy), or whatever else combats the alienation. Bring whatever you need to pray that is portable. You'll need it.
If you have caffeine issues
Some of us might have a problem. I acknowledge that up front. That said, I occasionally travel with pre-ground coffee of my snobbish choosing and a travel mug with a built-in French press system. You can usually get heated water from the hotel coffee maker. I have also, for extreme emergencies, traveled with those instant packets for coffee and cold caffeinated drinks, along with an assortment of tea bags. I'm referring to Starbucks Via coffee for the morning and the Refreshers for the afternoon. Does this make me a sell-out to not-good-corporate coffee? Yes. But my survival is at stake, so I don't care.
(Update: across the street from the Oregon Convention Center is a Starbucks and a Dutch Brothers Coffee. But if you're me and you need caffeine before leaving your hotel room, see above.)
When attending an assembly in a real city, you may want to be prepared to requests for food and money from those folks who find themselves living on the streets of that city. Tips: You can share your breakfast bars, or purchase two cups of coffee (one for you and one to give away). You can bring gift cards for fast food places, or clean socks. You can even just acknowledge people, say hello, even if you don't have anything material to give.
What am I missing? Post in the comments!