Scout,
If you are lucky, you can do some things while on PAT. It is a limited role that will allow you to put on the uniform, learn about some of the kit, attend lectures on rank structure, drill, etc. There may be other opportunities that present themselves throughout the year, but they are not the type of things you would read about in a recruiting poster. It is a great opportunity in my opinion, but what is available will depend on where you end up.
My point is if the Unit you intend on joining has a letter for you to take to the recruiting centre, take it and get all of the initial hurdles out of the way. That way you are just waiting on a date for your course, you have secured a spot, and you should have your kit sorted out. Any number of things can happen and you might find yourself on course sooner than expected. The worst thing that can happen is that you will have to wait a while for a date.
If you have any more questions, let me know.