I did similar when I was 25. I got the rep job first though before I went, so that way I had flights and accomodation etc arranged before I left. If she rang round a few big companies now she might find they are desperate for last minute staff even though it is the start of the season, but she may 'hit lucky' That way at least you know she had something solid on arrival. Reps jobs are normally applied for around oct before the season starts, but it is very hard work and lots give it up after a few weeks.
She's just going to go there and see what happens? On her own or with a friend? No wonder you're in a state as her mum but I have to say I was the same at that age and the situations I got into... Looking back on it, I hope my dd doesn't do the same.
How about hunting around on the web for a bit, get some information together, places she can go if things go wrong, hospitals, English speaking activities etc? There must be a sizable expat community, so bound to be an English church community, for instance which is always a good place to ask for advice.
Being me, I would probably buy her a one-year return ticket so she could come back at the drop of a hat if things go wrong and look into health insurance. She can register with the embassy when she arrives, although I have never done this myself.
I think at 22 you'll have to rely on her using her common sense but being the clucky mother-hen type that I am, I would probably even go over with her and see her settled! My poor dd, she's only 5 though so I may loosen up a bit before she leaves the nest.