If you are worried about the book/show setting not being very accommodating, you could always have it take place before Aegon's Landing. I believe that timeline is very much a blank slate up until Aegon comes along. The families back then were different too (Hoare, Gardener, Durrandon). 

Another possible setting could be during the Targaryen civil war (the Dance of the Dragons). Players could choose a side to support. The only problem I see is that show-watchers would be unfamiliar with the setting.