Played a solo game with Mandy the Researcher. Took about 2 hours since I was learning the game and won with only 5 doom tokens on Hastur. The mythos cards I drew were lucky and Mandy is uber, but I can see how solo play will be easier than group play.
The one investigator got all of the resources and only had Midnight every four turns. In a 4 player game a person typically gets just one turn per Midnight and you spread out the resources each "day".
With the one player it was worth my turn to buy trophies several times in a row to prepare for an adventure and get it done before Midnight. Can't do that with more than 2 players.