I don't want to give away too much information about the cache. This is meant to be difficult, but definitely not impossible. As such, you must use your brain to figure out what to do, but I will say that everything you need to find is hidden near the original coordinates. Please be sure to put everything back as you found it.
The difficulty rating applies to the cache as a whole. The terrain rating applies to the first part of the cache only. The rest of the cache is a terrain rating of 1-1.5 (don't make it harder than it has to be).
There's room in the cache for several small swag items. IMPORTANT: You must sign the log to be able to post a find on this one! No cheating. Also, don't post any spoilers in your logs; please allow others to have the enjoyment of discovering it for themselves and figuring it out without spoilers.
If you're stuck or need any hints, feel free to send me a message.