Geert Vinaskov wrote:
For instance: The keeper has a maximum handsize? Apparently that rule is only mentioned in the keepers guide...
Core rulebook, page 11 wrote:
All Mythos and Trauma cards in the keeper’s hand are kept secret
from the investigators. The keeper is limited to four Mythos cards
and four Trauma cards in his hand at any time. If he ever exceeds this
total, he must discard cards of his choice until he has four.
As far as I know, all you're missing is the scenario-specific information. Which is still rather a lot. It's easy enough to find photographs of the maps online, but how will you know what cards to seed?