I will be doing a caricature gig tomorrow at a wedding reception and I am really looking forward to it. My client has requested a particular size paper so I went to Arizona Art Supply and got several pads of premium 100 lb vellum. I am cutting the pads down to size today and that is all that I really need to prepare. When I arrive at an event, all I need is some chairs and a small table. I don't use an easel or anything complicated like that. I draw in black-and-white with a fine point Sharpie permanent marker.
So, all I need to carry is the pads and the pens. I usually bring way more paper than I will need and lots of extra pens. This not only is the most professional way to go, but it a preparation technique that I learned years ago for teaching. It's normal to be a little nervous before a performance (and that's what I am doing, a performance that is supposed to be interesting and fun) but if you are well-prepared that makes everything better.
Once I start drawing, it will be fun. It always is!