My friend is a sahm and in her case this means money is tight. There is a show we both would love to see. After a wine or two I rashly said let's go my treat. I mentioned dinner and the concert. She still lives in the city we grew up in. She won't leave her DC with her DH and doesn't like to socialise on nights out/away. I was surprised and pleased when she said she would like to come here so I said I would spring for a hotel.
She has sent a text asking 'what should I do about travel?' 
She drives and she could buy a very reasonable advance ticket for the train (£11 return). She has does have some spare cash. She is off to the cinema and has gallery tickets (about £20 each I think). If this was the other way around, I would expect to contribute something. I would pay for drinks and breakfast.
AIBU in expecting my friend to pay for her own travel? 
Should I have expectations regarding a contribution?