あなた can go on the アドバイス spot for this if あなた want; I would be glad to help あなた out.
I'll just skip to the point, instead of 書く something long: I think あなた should just be honest with her and tell her that あなた don't wish to go. I'm sure that she'll understand you.
Wait, can't あなた solve your own problems? Anyway, there is nothing wrong with camping...obviously from the other shit you've 投稿されました あなた need something that will get あなた away from your stupid boyfriend and his stupid friend.
Do あなた know the only time I've EVER done something for the holidays? Oh wait, the last time was never. I hate camping, but I would KILL to go with my family.
If it's because あなた don't like camping, maybe consider it if あなた haven't already, at least for your mom? :]
If it's because あなた want to spend the holidays doing something else または just don't feel in the mood for it right now, just be honest with your mom, I'm sure she'll understand and be glad あなた were honest with her. :]