Macro Game for Hoard of the Dragon Queen Sandbox

If you're running a sandbox version of Hoard of the Dragon Queen, you really want there to be a possibility of failure should the players not do well. Accordingly, you want their efforts to translate into success if they play well. Also, we want to ensure that the cult isn't just standing still. If the players waste time, the cult is going to summon Tiamat.

To that end, let's use a victory point system, where VP = XP.

• Start the cult with 90,000 XP and two dragon masks (red and black)
• Each dawn:
• has the cult leader Severin been slain? 
• if yes, have 3/5 half-dragons (white, red, black, blue, green) been slain? 
• if yes, endgame condition the time has not arrived
• else, continue
• else, have all 5 half-dragons been slain?
• if yes, endgame condition the time has not arrived
• else, continue
• subtract from the cult the XP that the PCs have earned during the day
• if this brings the cult's XP to 0 or less, this triggers endgame condition the time has not arrived
• else, proceed down the list
• award the cult XP:
• 100 for the income of miscellaneous hauls
• 10 for each compromised minor city (begin with 30, for 300 XP)
• 100 for each compromised major city (begin with 6, for 600 XP) 
• if this brings the cult to 100,000 XP or more, this triggers endgame condition the hoard is ready, which persists as long as the cult maintains 100,000 XP. 
• else, continue
• does the cult have all five dragon masks? 
• if yes, endgame condition the masks are assembled
• else, continue
• The cult gets XP when:
• a PC dies (XP = the PC's current XP)
• the dawn arrives (as above)
• The cult recovers another dragon mask from a dungeon when:
• 15 days pass
• of course, if PCs recover a dargon mask, the cult attempts to re-recover it from them with assassins and armies and whatever other methods they can bring to bear
• there is no obvious way to destroy a dragon mask
• Endgame conditions:
• time time has not arrived (player victory): the cult ceases its raids and waits for generations to strike again.
• the hoard is ready (cultist victory 1/2): a sufficient hoard has been assembled at the Well of Dragons to placate Tiamat upon her arrival, but the masks must be merged to summon her.
• the masks are assembled (cultist victory 1/2): the masks have merged, but a sufficient hoard must be assembled to placate her upon arrival, or else the summoning is pointless.

All the cities are compromised by the cult: tax money is being sent to support it. More details on this coming up, but a big portion on the sandbox can be done in cities, ferreting out cultists and those compromised by the cult. 

These numbers may be terrible! I don't know! And, since I don't think there's a summary of who has all the dragon masks (I only know about Rezmir having one; maybe there's another mentioned somewhere in there), I'm just assuming they've got 2/5, Rezmir and Severin having one each.