CACHE IS NOT AT THE LISTED COORDINATES
This is the FINAL cache in the series of (6) other caches that I’ve placed at various public access points around Lake Koshkonong. You do not have to find any of those caches in order to figure this puzzle out. However; you may want to take a look at each of the cache pages to help calculate this cache’s actual coordinates. For your convenience; below are links to each of the cache pages in the series. 
View Of Lake Koshkonong I
View Of Lake Koshkonong II
View Of Lake Koshkonong III
View Of Lake Koshkonong IV
View Of Lake Koshkonong V
View Of Lake Koshkonong VI
North: 42 5a.bc5
West: 88 5d.ef2
a = (377MMMCMXC) - III
b = (366MMMMMMMMXXXX) + III
c = (377MMMCMLXVI) - II
d = (377MMMDCCCXLIV) + II
e = (377MMMCMXXIV) + III
f = (377MMMDCCCLXXXVII) + VI
The cache's hiding spot offers a fantastic view of Lake Koshkonong, and I hope you agree. Take some pictures and enjoy. I've placed some binoculars in the cache container for all to use. Please leave them in there for the next person to use. Everything else in the cache is fair game for trading, taking, or leaving! This cache's hiding spot is meant to be high terrain and requires just a bit of monkeying. The intention of this cache locale is to make use of a kayak, canoe, or small boat to gain access - (Reason for the T5 rating). It is possible to get to GZ by a MAJOR bushwhack that I'd advise against. The area around ground zero is a bit rugged. Please use caution.
This cache can be obtained when the water freezes. If you’re not familiar with the nearby landscape, lake, river, or small feeder streams/creeks please do not attempt this during the winter. Ice conditions vary and depending on which way you decide to gain access, it could be a problem.
Permission has been granted by Mary Nimm, of the Jefferson County Parks Department, to place this cache. The proper Jefferson County Parks Geocache Permit has been submitted and approved.
Have fun!!!
Congratulations to rcflyer2242 and wingwalkers on the FTF!