Typical set up/menu for farmer's market coffee stand? What equipment is pretty typical for a coffee stand at a farmer's market?  I would like to server pretty standard drinks including drips, pour overs, lattes, espressos, etc.  What are suggested menu items to have to really establish a clientele, but to also not go overboard on expenses, and what equipment is generally needed to open a stand?
Off the top of my head (by no means exhaustive):
A two-group double boiler espresso machine
You want two groups in case something goes wrong with one of them, you're not out of business. You also want to be able to use the steam wands while extracting, so the need for each group to have a double boiler is pretty big.
Instead of one machine that costs a ton, you can get two machines (each with one group and a double boiler) that cost anywhere from $1000 to $3500 instead. Try not to go with home appliances - even though I have nothing but great things to say about Breville, they aren't designed for that kind of continuous duty cycle.
Redundancy is not all that's important, you need to be able to make more than one drink at a time :)
At least two burr grinders with dose control
Dose control gives you consistency. And you need to be able to grind as many beans as you plan to offer without cleaning grinders each time. These can get insanely expensive as you get into features like auto tamping - the biggest thing to look for is accurate dose control.
I recommend a model that fires once you stick a portafilter under it, with a button to extract into a pitcher. They sometimes come with a small stand to tamp, if not, grab some of them (if not auto-tamping).
Refrigeration
I don't recommend using a cooler with ice for dairy - it's going to start off as too cold and work its way up to being too warm. A small dorm-size fridge would be better, and cheap enough that you can have a backup you can run home to get if you need it. Get a good fridge thermometer to figure out the ideal setting for the fridge (usually a dial between 0 and 9), mark it with a sharpie once you get around 35 degrees Fahrenheit (don't buy one that won't go below 40 degrees). Remember that fridges have cold spots, so measure at the bottom as well as near the coils (where the ice lives).
You also need refrigeration for you, too. Nothing says gross like sweat falling into coffee! An evaporative air cooler, or at least some fans really help.
Misc Equipment
Your pour-over setup, some presses, tables, rubber mats, pitchers, various kinds of spoons, condiment / syrup dispensers, napkins, etc. Don't forget cups, sleeves, alternative sweeteners (be nice, buy honey from a vendor there, helps business). Also, don't forget corrugated trays (recycled) for large orders.
You can also never have enough cotton bar mop rags. Don't forget a camping stove or induction cooker, and if you use an induction cooker, make sure everything you need to put on it will work.
If you're going to be blending stuff, get a good blender that can eat through ice easily. Another thing that's nice to have two of in case one breaks.
Don't forget, you need to be able to wash your hands. Sanitizer is good, but having a basin and bucket is also helpful.
And, don't forget whack-buckets, trash cans, etc.
Ticket Handling System
This is really important. Imagine you have 20 people lined up and 10 orders going. Make sure you know what people ordered, what needs to go out next, and that the tickets are clear. Soy instead of whole milk? Make sure the person making the drink knows that, and that it goes to the right person.
POS (point of sale) systems are increasingly cheap and really help with this. But old fashioned pen and paper tickets work well too, if you have a system in place. This is a really bad way a great setup can fail if you don't get it right.
Water
You're going to need some big plastic bladders full of clean filtered water. You'll also need to make sure it's possible to get that water into the coffee machines easily :) Transporting that much water can be a challenge because it can get so heavy that applying the breaks in a normal vehicle takes on a whole new dynamic. Got a place that delivers it?
Testing
Make sure you do a dry run, that's the only way you'll be sure you have everything you need.
Everything else is pretty unique to what you want to offer, but if you keep it simple it's not too bad. If you're going to offer cakes and snacks, have a way to keep them fresh.
Menu Items
Keep it simple and keep it confined to what you can make consistently well. Tell people they're welcome to ask, but avoid anything super complicated from becoming a permanent fixture on the menu.
Cost your drinks
You should charge 3x your cost to be safe, 2 - 2.5x if you want or need to be really competitive. 3x is pretty certain to cover your costs, overhead, and profit. You need to know how much it costs you to make every single thing, how much it costs to just open and tear down, and everything else. Another great reason for keeping a simple (10 things is good) menu.