The real map is just the house and then the woods to the graveyard. Luckily you have a map. Follow it to the graveyard and look at the cool gravestones. Asa Royal Stench?? :) But there are four key ones - the four dogs. Just like in the house. They are:
Xander - Aug 16
Vitus - Feb 8
Iggy - Nov 11
Lucy - Apr 4

Note how each is in its own season? Also note that each starts with a roman numeral as the first letter. Lots of clues!

OK, there's a board on the ground here. Take it. There's another back at the house under the tarp. In the front of the house you meet a birding guy. He tells you about Jeff Akers the ranger. He tells you to talk to Jeff about testing the well water. When you head inside, the ghost dogs attack. It's sort of scary! They don't get in, not to worry.

Head upstairs to sleep!

Nancy Drew Ghost Dogs Walkthrough