To give you a general idea...
The oncology service at Penn is composed of Dr Lackman (chairman) and Dr Ogilvie. They operate mainly out of Pennsylvania hospital. As a student you will be on the onc team that includes a PGY4, PGY2, and some interaction with a PGY1. There are usually one if not two med studs on this service between June and October. It is a busy service with plenty of interesting cases that are done at only a handful of institutions across the country. There is tumor conference once a week, grand rounds at HUP once a week, and other conferences that you may or may not attend throughout the week (there is no shortage). You will round in the mornings and then either go to the OR or to clinic. Your day will end when the OR is over or when clinic is done. Though Pennsy is mostly elective surgery, you will see a number of fracture cases come through the ED. If time allows and if there arent other medical students on the services of Dr Keenan (Neuro-Orthopaedics) or Dr Heppenstall (general ortho/joints), you can take advantage of scrubbing in and spending some time with these members of the senior faculty as well. During this month, you will not take call at Pennsylvania Hospital, but will have the opportunity to take call at HUP (main hospital and busy trauma center). This will be an opportunity to meet and interact with some of the other residents.
As for any away, same rules apply... work hard, get involved, read for cases, dont be annoying, etc.
