Thanks all for your info.
@MissConductUS as PP said, American Studies is a well-known degree here, and DD is really enjoying it (and doing well as well). Glad to hear that Wilmington is well thought of - I have to admit I'd never heard of it before DD said she was going there!
To answer some other questions, she hasn't started her visa application yet, as she hasn't had her SEVIS number from the uni yet. They do seem to be on the ball there, though - she has an email address and online account set up with them. They have provided detailed step-by-step instructions, although I must admit, having looked at the website etc, it does look quite complicated. We know we need to be on the ball with it though. Thanks for the info about the photos, will bear that in mind.
Re banking / money: we have a Halifax card already (avid follower of Martin Lewis) and I was planning to get one for her, as I thought it might be sensible. @Needmoresleep, is there any reason you recommend Monzo (I don't know much about them)?
Accommodation is already sorted & it is on-campus - she even knows which room she will be in and who will be in the other rooms. She has been relieved to be able to get a single room - she knew a shared room would be very much a possibility, and was resigned to that if necessary.
Medical insurance is offered by the uni & although I've been told it is expensive compared to standalone policies, it seems like the most sensible option to me, as we can be sure it offers everything the uni requires. She has no pre-existing conditions, but has been told by the uni she needs to get a doctor's cert and perhaps some vaccinations, which we will organise for when she's here in June / July. Will also get her a dentist appointment.
She doesn't drive & I imagine will be spending most time on campus, as that is where she will be living. In terms of travel around the States, it is something she wants to do, particularly at the end of her course, during the 30 day "grace period". She will be coming home for Christmas and possibly one other time (will depend how she feels I guess). Her 21st isn't until mid-June, when she will have finished her course, but this means of course, that she won't be legal to drink when she's there!
Apparently she may be able to get a job on campus, but she is hoping not to have to do that, so she can focus on her studies and making the most of her time there - she has worked in Hull during her first 2 years, so she isn't averse to it, but we agree that if she can be sensible with the money we give her, then she shouldn't need to.
Both unis have been helpful with the process to be fair - she has had a module this year all about the year abroad, where they had to create a dossier about every aspect of the year, showing that they'd considered everything, travel, courses, weather, politics, money, accommodation etc etc. The uni also hosted a meeting for parents last week, where we were able to talk to students who are now in their 4th year who offered some good hints and tips - the one big thing that came out of it was that homesickness is normal, but make the effort to get involved in things and it will pass. Also play up the British accent because they love it (we are from Wales, so DD will be even more of a novelty!).
She does have a boyfriend here, who she met in Freshers' week, and they are very much planning on staying together, but it is going to test the relationship, that's for sure.
Thanks again to everyone so far, and if anyone thinks of anything else, please feel free to chip in!