Jason,
Welcome to Pprune.
The best thing to do is get the exams done before you go, then all you will have to do is concentrate of the flying. You have already mentioned that there is alot to get through, but work your way through the study material for each subject. Did you get hold of the PPL confuser? If not it is welll worth getting. It is a book of questions very similar to those written by the CAA. It is a good tool to use to know what level the questions are pitched.
Once you have done this I would go through all the exercises of the PPL flying syllabus, 1 - 19, the blue Trevor Thom book is not a bad reference tool for this. Get all the basic procedures in your head and you will find the flying state side alot of fun, and if you are ahead of the game by doing the above it will give you time to relax in the evenings and have a bottle of USA mouth wash beer
.
Enjoy it, flying in the US is a lot if fun.