Regarding the laughter of the little girl, you failed to mention whether your mobile home is isolated or is located in a community of other mobile homes. If the latter, is it possible that you are hearing the laughter of a neighbor?
For the sake of argument, let's say you have eliminated, as best you can, all logical explanations for your experiences. What should you do? You mentioned an idea in your own question: Try to record it. Get a digital or cassette recorder, set it to record, and just keep it on when you go to bed. Then in the morning rewind it and listen to it to see if you have recorded the laughter or any other anomalous voices or noises. In this way you'll have some recorded evidence to deal with. If you're so inclined, you can also keep a written journal of your experiences. The more you document, the better.
So what do you do with the documentation? If your documentation begins to convince you that you really do have ghost or haunting activity in your home, you have a few options:
- Ignore it, since it seems to be harmless (except that it may be disturbing your sleep). In this way, you're accepting the presence, and you'll probably find that it will just go away after a little while.
- You can tell it to go away. Tell it, out loud, that its noises and laughter are disturbing you and that you want it to be more respectful and to be quiet when you're trying to sleep. You may feel silly talking out loud to "no one" like this, but sometimes it really works.
- If the activity gets worse, consider contacting a paranormal research group in your area to investigate. They may have some other ideas. And here's where your documentation will be helpful.