Maze explanation is here.
Startbonus: 400 coins
Collections: 600 coins every 8 hours (7200) = 7600 coins.
The total does not include coins we can get from quests or dragon tv.
For Collecting times check this.
Dragons:
Headstrong R #691: The path costs 860 coins.
Key for Coloseum on step 10 (460 coins)
LaW chest* on step 13 (580 coins)
Coloseum R #1178: The path costs 2825 coins + 1 key = 3285 coins.
Key for Robin Hood on step 16 (1915 coins)
LaW chest on step 13 (1335 coins)
Robin Hood E #215: The path costs 3635 coins + 2 keys = 6010 coins.
Key for Fortitude on step 20 (2640 coins)
LaW chest on step 13 (1370 coins) and step 22 (3090 coins)
Fortitude L #1403: The path costs 6020 coins + 3 keys = 11035 coins.
LaW chest on step 6 (465 coins), step 11 (1515 coins), step 18 (4020 coins)
Timelimited:

11.: Unbreakable L #968: The path costs 8145 coins.
LaW chest on step 3 (185 coins), step 21 (6330 coins), step 23 (7515 coins) 
11.: Warlord L #846: The path costs 6720 coins.
LaW chest on step 19 (5085 coins) and step 21 (6150 coins)
*LaW chest= Legends at War chests with arrows in them.