If you're thinking of using tampons then start practising with them now, they take a bit of getting used to.
If I were you I'd use a huge tampon and a huge pad together, surely you stop for toilet breaks though, they can't expect you to not use the toilet for 10 hours straight, plus you'll need to drink a lot of water so everyone will need to go at some point.
It's up to you whether you want to take some weird pills to delay your period, but please go to the doctor and ask their advice if you're thinking of doing this.
Also, tell a female friend or a female teacher or someone you trust who is also gonig on the trip, and explain that you really need a moment to freshen up at some point, then at least you have someone there to support you whatever happens
good luck anyway, and I hope you have fun despite annoying female bodies!