Ignore the text on page 6: “At the start of each player’s turn, he must draw one dragon token at random from the pool and resolve its effect”.
When a Character in the Middle Region, Inner Region or Dragon Tower is instructed to draw one or more Adventure cards, instead draw an equal number of Dragon tokens. Resolve Dragon tokens in the order in which they are drawn.
When a Dragon Scale is resolved, draw a Dragon card of the same colour, which must be encountered as if it were an Adventure card. Then, place the Dragon Scale on the matching Draconic Lord.
My purpose with this variant is to limit the extent to which the Dragon expansion overwhelms the main board and its Adventure cards.
This variant limits Dragon activity to the Middle Region, and the middle to late stages of the game. It also delays the administration of the Dragon Scales until the midgame, to avoid the players becoming fatigued.
The Middle Region effectively becomes a more dangerous Dragon-themed Region, on a par with the Dungeon expansion board.
Dragon Scales and Dragon Cards will only begin to be drawn during the midgame, or if Dragon-centric Characters seek them out earlier. Characters are therefore unlikely to acquire so many Dragon Scales that they are overpowered.