I attended a series of company schools there in the early to mid 90s. We always stayed at the Marriott on Dock St. From there you can go to Penn's Landing and they have a lot of things to see, including the Olympia and a WWII sub.
https://www.phillyseaport.org/
The school itself was in the old Public Ledger building, just across the street from Independence Hall. There's a little street behind that building that is full of jewelry stores and places to grab a slice or a cheese steak. I can't remember the name of the street, but the locals called it Jewelers Row.