Okay, now for the answers:
1:
Spoiler
3 - Two on the main road and one in Gerdur's yard
2:
Spoiler
5 - The three watch towers, the mill, and the pier behind the mill
3:
Spoiler
1 - Rain doesn't change the scenery
4:
Spoiler
10 - 6 behind the Sleeping Giant Inn and 4 at Faendal's house
5:
Spoiler
20 - from top to bottom: 4, 5, 5, and 6
6:
Spoiler
6 salmon hang from the rack
7:
Spoiler
4 - 3 behind the mill and 1 to the left of Gerdur's house
8:
Spoiler
It's a boar's head
9:
Spoiler
4 - 1 on the main road, 1 in front of Alvor's blacksmith shop, 1 next to Sven's house, and 1 behind the Sleeping Giant Inn
10:
Spoiler
Trick question, as there is only one answer and that's AFTER speaking with Balgruuf and AFTER speaking with Farengar. Even though Balgruuf tells Irileth tells her to send guards to Riverwood, she will not do so until you speak with Farengar. If you leave Whiterun after talking with Farengar, you can actually follow the guard to Riverwood. Once they arrive, they take over two of the guard towers, preventing Frodnar from standing on the south tower for the remainder of the game.