jb,
Well done getting a job offer so quickly! I can't offer you a temporary job and although I have had temporary ops jobs in the summer, I do not rate your chances in aviation at this time of year.
As an ATCO I am always keen that pilots should see how things look at the other side of the radio and commed you for your enthusiasm. If you get the chance I would highly recommend trip to Swanwick, but fear that you may only be able to do this as an official trip through your company (I would be glad to be wrong). I doubt that your local airfield woud turn you away if you wanted to spend a day or two gaining an insight into ATC though. I often have pilots and wannabees watching my work and hope they go away with some idea of how the system works.
Happy to help with a tower visit - PM me if you're interested.