I did a search on Prosperous Lake. Some links are placed below that you might find interesting.

Ingraham Trail Map (Hwy. 4)

Winter Road Updates for 2008. -- What might be useful about this one is: Look in the address bar of your browser and notice where it says 2008. Next fall, if you change 2008 to 2009, you might get the 2009 winter road updates. Try changing it to 2007 and see what I mean. Make sure there is no spaces.

At this link you can see some small maps: click on maps.

This one was posted in November 2007 and talks about ice road changes going to be done.

Yellowknife Green Map It's a 2 page .pdf document with 2 maps on one page. You will need to enlarge the page size a fair amount.

Great Slave (NWT) Ecosystem I don't know if this would apply to some of the places around Tyhee's properties, but, I doubt very much that Dave Webb would want to argue with one of these fellows. lol!
Note where it states: Remember to keep your distance from the wild buffalo – they can be dangerous if disturbed.