Thank-you everyone for taking the time to respond
It helps a lot to be able to talk about this and to not be judged.
In regards to the father and child support, I really didn't want to talk about this, but since a few people have brought it up, I will address it. I don't know where the father is, and neither do the courts. A few years ago I sought assistance from a lawyer. Two separate private investigators have not been able to find him. He is not in the United States, Canada, Europe or anywhere else...kwim? No one knows where he is, and he doesn't have any relatives or family that anyone knows of, so I can't get help there, as much as I want and need it. It is really hard for sometimes, but I have come to accept it.
Now about DD2 working off the debt. I do want her to work, I know there is work she can do from the neighbors (besides babysitting) The only options to be a mother's helper are too far away, she get can't there by herself because I am at work. I expect her to work and pay me back for the guitar no matter what avenue I take, but the thing is it will take her a long time to pay me back, so even I don't give DD1 the trip money and DD2 works I won't be able to afford a new guitar for DD1 until Christmas.
The reason DD1 wants a new guitar is because she bought a BRAND new one, and it was only 1 month old when DD2 smashed it. She it still was in new condition, kwim? I also want to point out to the poster who said that it was rude for DD1 to not want to be in the same room as DD2, well at this point I am wanting to respect her feelings and not force her to do anything. She hasn't yelled at her sister (except for when it first happened) hasn't hit her, or otherwise been rude or mean or done anything like slamming doors etc so I think all in all she has handled herself very well, and I just want to let her express her anger since she isn't being in her sisters face.
I hope I don't sound rude or mean to anyone who replied, it is just that I am still really torn and so tired. I can't bring myself to make a decision. DD1 wants a replacement of the one that was broken, but DD2 doesn't want to miss this camp (I think she sees how much fun her sister had when she went) For more see my post a few above this. Again, thank-you for all the responses and encouragement.