DuPont in History

Welcome to my home town! DuPont has a long history, dating back to almost 200 years ago... Yet this is a very up and coming modern little community today, so please come vist out growing "downtown" area - read a book, have a slice of gourmet pizza, or a latte and some cheesecake in the little park... In order to find this little cache, however, you will need to find out a little bit more about Dupont's history.
Find the answers to the following:
1) Find the date the original Nisqually Fort was built (ABCD)
2) Find the date the second Nisqually Fort was built (EFGH)
3) Find the difference between the dates in 1 and 2 and divide by 2 to get I
4) Find the date that the City of DuPont was incorporated (JKLM)
5) Find the date that Weyerhaeuser Company bought the land that is now Northwest Landing (NOPQ)
6) Find the date that "The Village" housing was started for permanent employees of the DuPont Company (RSTU)
7) Subtract date 4 from date 5 get VW (hee hee hee)
Plug into the formula: N47 TW.GPV W122 CB.ILM and go find!!! There is a high potential for muggles being about so PLEASE hunt with stealth - also DO NOT fondle any foliage. It's not located in the garden area. Log only - bring your own writing instrument.