Thought I'd update this thread (just in case there's anyone interested). Dd is safe in the US, flew out on Saturday, had to change flights in Charlotte, NC, which we were a bit nervous about, but it all went fine. The uni put on shuttle buses from the airport to the campus, and by all accounts her arrival was very smooth.
Getting her visa went smoothly as well in the end. Luckily we have relatives in London so her and her boyfriend stayed with them for a couple of days and made a bit of a break out of it.
We didn't go with the Uni medical insurance in the end - once I'd done some investigation, I realised it was about 5 times the cost of buying a standalone policy. The one we got covers everything that is needed, and has been accepted by the uni. Our doctors' surgery gave us a list of all of her vaccinations, with the relevant dates. She didn't get herself organised to get the ones she was missing (Tetanus and Hep B) while she was still here, so will have to pay for them over there, but they aren't massively expensive (in fact cheaper than in a travel clinic over here).
I would say the visa, the medical insurance and the medical / vaccination history were the most complicated bits of bureaucracy we had to deal with. I haven't yet paid for her accommodation and meal plan (compulsory, no self-catering option available in her dorm), and it seems like paying for it by bank transfer might be a bit complicated, involving a trip to the bank with a bit of paper from Western Union, but time will tell.
Have had a video call with her today, so we've seen her room and a bit of the rest of the dorm. She says the weather is hot, but what has really hit her is the humidity - like nothing she's experienced before she says. She's made some friends, and had a day at the beach with them yesterday, with her first lectures today. She seems happy and relaxed and it's put my mind at rest to have had a chat with her.
This stream of consciousness may not be of interest to anyone, but perhaps someone in the future may come across the thread and learn something useful - I know I did, so thanks again to all those who contributed.