Game length depends on what kind of gametype you join. There are multiple options to set up your own game (as a host) or multiple games looking for players that are open to join (game que). Once a game has enough players though it will start.
There will be time periods in which you can play a minigame and time when you can cast a vote. If you are going to be super busy though you can opt to play them a day or two in advance,.. this is where it gets tricky. The social aspect of the game requires you talk and strategize with the other players so there is a necessity for paying attention to the game for the duration of the game if you want to do well or have an enjoyable experience with it.
Any and all ideas are still open though, Billy and I are still looking at our options for this so it works around people real life schedules too.