Boot camp training is located in Great Lakes, Illinois.

I kept a diary in boot camp.  I wrote in it as frequently as I could as the only form of self expression I could produce without being screamed at.  I wrote in it at night when everyone were to get into their racks.  It was the only time I could finally be at peace, free to finally spill my thoughts and frustration onto paper.  One time I was writing and the female next to my rack told me I should put my notebook away; they would confiscate it.  Unless you are causing trouble, it is highly unlikely an officer would go into the compartments and check the racks of all 80 recruits for writing in diaries.  It is easy to keep one and hide it under your pillow should an officer step in late into the night. 

I highly encourage everyone who goes through boot camp to keep a diary, not just to record your experience, but also as a way to keep your sanity!  It is also a way to test that you are still capable of thinking for yourself, which probably defeats the whole purpose of boot camp.