If you have memorabilia or photos, take them to help talk about shared memories.
Ina slightly different situation, I read a favourite book to a dying friend, and I have read poems that recall memories.
I am not musical, but my mother was helped by a young friend who sang favourite songs.
Of course, our suggestions may not be right for you & your friend - only you know. Champagne is often tolerated by those who can tolerate little else, and a few sips are unlikely to upset any medication at this stage (but of course you would check). A 1/4 or 1/2 bottle to share and toast your friendship might be just the thing.
Tears are streaming down my face as I write this, as I have done this 3 times now, for friends who have died too soon - I say 'thank you' for all you have meant to me, for all you have done, for all we have shared.
If you can, check the burden of your own grief at the door. Your friend will expect you to cry, but she will do best if you can keep to what has been good, and what you will carry into the future.
And very kind to stay in a B&B so you are not 'in the way'.