One of my friends has had a bit of a miserable time of it so for her birthday I was more generous than I would normally be. She wanted to see a theatre show that is on in a city about 2.5 hours away so I told her to keep a night free and booked the tickets and a hotel. My friend was over the moon when she opened her card.
I was speaking to another friend about it and she queried whether I was covering the travel costs (you just turn up and pay on the day) and I said I would. She then asked if I was covering all meals and I said I hadn't planned to. This other friend then told me I was 'out of order' buying someone a gift that would cost them money.
YABU- you should cover all expenses on the trip as it was a gift.
YANBU- the hotel/tickets/travel is the gift and she won't expect you to pay for food/drinks.