Need Networking Advice!!

I'll begin with my background, I am senior at a non-target university (Think top 150). I am studying Finance, and I currently have a 4.0 GPA. I am graduating a year early, and I plan on pursuing a one year masters next year to have access to OCR and a stronger alumni network. I plan on pursuing my masters at Vanderbilt, Texas, or UVA, and for the most part, I should know of my acceptance by November/ December.

So essentially my goal is to secure some sort of SA position before my masters begins; however, I would like to use the alumni network of the more "prestigious" school I get accepted to. If I have been accepted to the university, and I plan on attending is it okay to put this on my resume and network with said university's alumni before the program actually begins? Anyone been in a similar situation and have any advice? Will alumni be wiling to help if I haven't even attended the program yet?

Thanks in advance for any helpful insight/advice.