Your first year will be overwhelming. There is a lot to do and see. I would recommend against seeing talks at the con, unless you REALLY want to. The lines get long for the popular ones, and videos of them are posted later online anyway. Look at the villages, contests, other events going on and have at; thats the best way to meet new people and learn new things. The DEF CON secure wifi is actually pretty good, but I wouldn't really mess with it unless you really need to get online for something. I would recommend against cellular, as phony sites have popped up every year.
I'm usually in the HHV and wearing a green dragon knit cap to stand out, <shameless plug>so come on by, say hi, take a stab at the RE challenge and the BYOB (Brain) contest</shameless plug>.