Oh you'll have so much fun. What airline are you flying? Please say British Airways...they are the best and have tea service, which is just awesome.
I assume you'll be taking a red-eye there...just try to get as much sleep on board as possible. Will your friend be picking you up to take to you Essex or will you be taking the bus. The bus is very accessible and easy to navigate. Public transportation in the UK (in general) is much better than a lot of US public transportation.
Will your friend be spending the whole time with you or will he/she have to work during the weekdays? There are a lot of things to see in the UK and it's really a pretty small island. If you are staying for two weeks, I'd try to do a few days in Wales if you can swing it (book into a B&B, they are nicer and less expensive than hotels). It's really not far of a drive and is just stunning! Check out the British National Trust (
http://www.nationaltrust.org.uk/) - there are lots of properties around Essex that would be great cultural things to see. Spend some time in London too since it'll be so close. Maybe take in a West End Theater show -- I did a girl's weekend in London for my 30th birthday (we were living in England at the time) and we saw Wicked...it was AMAZING!
You'll have a fab time! It's an amazing place! We're dreaming of getting back there!
Also make sure to see if your sorority has an alumnae group there -- you could hook up or get some local advice from those living nearby. :-)
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There are friends who pass like ships in the night, who meet for a moment, then sail out of sight, with never a backward glance of regret...Friends we meet briefly then quickly forget.
Then there are friends who sail together, through quiet waters and stormy weather. Helping each other through joy and through strife. And those are the kind who give meaning to life.
~ ⚓ΔΓ⚓ ~