A REALLY lightweight chair to carry easily on the walk over to the main area for seminars and to evening campfires.
A red flashlight so as not to blind people while walking around at night.
Sunscreen
Add a hide-a-key on your vehicle and bring a car battery jump-starter if you have one. There were a few peeps with dead batteries and a few that lost keys or locked themselves out of their vehicles.
Love the baby style wipes and "no rinse foaming body cleanser" which works on hair as well. I found on Amazon.
"Contact" cards with your info in order to easily share your phone/email/etc. with people you meet.
A pen/notepad at the ready to note new info
I am planning on chilly nights/early mornings and warm- ish days, so layers! Desert friendly footwear i.e. sneakers, boots and ugg-style comfies. Just be comfortable.
All the water I can carry and easy to prepare non-perishable foods like soups, 90 second rice, and other canned veggies and fruits.
Last year was a blast! Keep in mind it is no big deal to easily pop into town to re-supply or pick up anything you discover you might need. It also wouldn't be surprising if your neighbors loaned or gave you whatever you might need!
I hope this helps - see ya @RTR2019
Note-
I am trying to come up with a way to store trash in my rig until I can properly dispose of it..maybe some type of sealed container to store full (grocery bag) trash bags as I go along? I haven't figured that out yet, but am thinking about ways to minimize how much trash I generate.