I really like Trans-Pecos, although I do not have one. I do have two corn snakes and love them. I've also heard good things about Baird's.
My two cents, if it's her first snake, or she wants something easy to care for, you cannot go wrong with a corn snake. Great personality, docile, great eaters, easy requirements (she can get a cheap glass tank - as long as it's escape proof).
They come in every color and pattern you can imagine. They are inexpensive.
The only drawback of any smaller colubrid, is that they are really small when very young. I would recommend she get a yearling +/- so it's not incredibly tiny and fragile.
Children's pythons have stricter requirements than all others listed, but aren't always as docile.
Regarding being active during the day. Corn snakes are active in the evening and early morning. I see them out and about in the evening hoping for food.
I googled diurnal snakes and this came up. Probably worth looking at.
https://thereptileroom.net/snakes-th...uring-the-day/