I have ordered from Harford several times so can answer. The website goes live to preorder, you pay half up front online, and then you'll get an email when the grapes are likely to be ready for pick-up. Last you'll get an email when they have arrived. The vineyard opens special hours to facilitate pick-up, so you'll want to let them know when you are coming. When you get there you'll pay the other half.
Crush/destem: if you want this put it in the notes for your order. It's $25. They'll do it for you on the day you pick up. I get this done because it's easier for me.
Bring your own buckets for grapes. The juice comes in pails, but the South African harvest is only grapes.
They sell yeast and malolactic bacteria there, and the winemaker (Kevin) can suggest a yeast pairing for you. If you want malolactic, let them know in advance and they can order.
Also, their website has instructions for making wine from grapes that are very useful.
They do not adjust pH, acid, brix, inoculate, etc. The grapes and juice are unaltered and fresh.
They grow grapes there, and they bring in grapes and juice from all over. They sell their own grapes, which are merlot, traimenette, and a few other types. I got Maryland Seyval grapes there last harvest, and it is very tasty.
I really love Harford for their customer service and the fact that I can get Italian, Californian, Maryland, Chilean, and South African juice and grapes. Plus the prices are really good. Most juice pails are $52.00, and they only do pick up so you're not paying shipping.