Hi,
Don't try to solve all these questions in one go. Take them separatly and onc eyou master each one of them you will be able to piece them all together.
there is two big chunk, one is the turn based system, the other is the board layout and what can be done.
for the turn base game, it's best that you can play your game purely in theory without any 3d world, just a pure mathematic representation of your game logic, so that you can test the various aspects of the turn based management. It's not simple by any mean, but don't over think this as well. Start with a simple game like dice ( the higher dice results, wins the round), that's simple enough to get you started.
on the board itself:
you need to create a "matrix" of your game flow, to control movements you can do that on the fly with inter connecting each slots with their neighbor so that a slot would know where the user can go from here, but you could also use something like xml or some other text based description of your board and use Ids to represent slots, so that in yout 3d, you can assign ids to your 3d objects and they will refer to that text based description to that what they can do.
within that, you will also need to separate the movement procedure, again, make a simple board game with no purpose, just 3 slots, and try to move your player around with simple command.
once you get acquainted with the above, you will be in a better position to achieve your final goal
So, as you progress, don't hesitate to come back to their forum and ask more questions ( in new threads) about the specifics of what you are currently trying to achieve ( be it turn base logic, board management, movement, etc)
Bye,
Jean