Regular intercity bus traveler here. I take the bus by myself maybe every two weekends on average–been doing so for several years–and I’ve never felt the need to carry pepper spray. (Deodorant spray, sometimes, but I’ve never feared for my personal safety, and I’m a small woman.) I don’t know how often people travel by bus in your part of the country, though–I’m in the Northeast. Buses from NYC to Boston, Boston to NYC, Massachusetts to wherever, are often packed.
How street-smart is your daughter?
When I was 17, I really wanted to visit one of the colleges I had been accepted to. My father couldn’t accompany me to Massachusetts, and he was reluctant to let me travel to or within Massachusetts by myself. I asked my cousin, who lived there, to speak to him. Luckily for me, she was able to convince him that if I was able to navigate the New York City subway system alone almost every day for six years, the Boston T would be a piece of cake. I didn’t have any problems on my trip.
I agree with the tips that other people have offered:
If you can accompany your daughter to the bus gate, speak to the driver and let the driver know about your concerns for her safety.
She should sit by herself (and keep to herself) if possible.
Pack light. It’s awkward carrying several bags all by yourself. Even wheeling a suitcase around can be a pain.
She needs to keep an eye on her luggage, especially if bags are going to be transferred or unloaded before she reaches her destination. Put an address label on her bag. I like to carry my travel bag with me onto the bus and put it on the seat next to me.
Tell her not to leave the station before she gets on the bus and before she arrives at her destination, if there are any layovers. You don’t want the bus to leave without you. And if someone is going to pick her up, she shouldn’t be wandering around or outside the terminal where she gets off.
Bus trips can be quite boring, so bringing along a book is a good idea. (With all the road noise, sometimes it’s hard for me to hear my CD player unless I turn up the volume all the way, and I don’t like doing that.)
Make sure she has detailed directions to wherever she’s going and enough cash to cover emergencies (like if she has to catch a cab at her destination).
Bus stations can be worse than the buses themselves, true. I was surprised at the shitty condition of the Greyhound terminal in San Francisco. It was like a ghost town. (The Boston bus terminal is really nice, and Port Authority in New York is okay.)
Oh yeah, I prefer Amtrak over the grey dog if I have a choice. The train is WAY more comfortable (and cleaner).