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:
Yoyo -R- #262: The path costs 860 coins.
Adventure -VR- #309: The path costs 2825 coins + 1 key = 3285 coins.
Brave Sword -E- #326: The path costs 3630 coins + 2 keys = 6005 coins.
Glaive -L- #1517: The path costs 6020 coins + 3 keys = 10830 coins.
Timelimited:
6 - 9?: SSSniperWolf -L- #1524: The path costs 8165 coins.
8 - 9:- Ravagar -L- #1338: The path costs 6720 coins.