I know you have quite a bit on your plates now, but what about the other Burroughs books?
Tarzan might not be good for a large group, though.
Pellucidar seems like a no brainer.
Carson of Venus anyone?
The Caspak adventures might make for a great time travelling book.
Other ideas for John Carter? Long term might have his adventures on Jupiter....
"There -is- hope for the future.
When the world is ready for a new and better life...
all this will someday come to pass.
In God's good Time."