Thank you for your reply.So I'm going to do this. Set the position, rotation, velocity and angular velocity at the earlier of the two frames next to the desired time. Then advance physics by the difference between the desired time and the frame time.
b)Save snapshots at some interval, then either interpolate or simulate forward/backward from closest point (whichever works the best)
This should be better than interpolating between two frames myself, because a collision might happen in the meantime.
I'm not sure what your specific use case is here, but be aware that physics systems don't like 'teleporting' collision geometry around. It is a slow process. Consider it (some what) equivalent to setting up the initial scene... more specially, when you teleport an object its potential collision lists will need to be re-updated entirely, rather than the presumably more optimized process used when moving an object with velocity. (Obviously every system/engine is different and this may or may not be applicable).
With the snapshot approach, while 're-winding' you don't need to move all the collision geometry around (only the visual geometry)... only once you go to re-start time do you need to move the collision geometry to the new location (and probably best to do this with a completely re-load of the physics world). This will only result in a performance spike when restarting the simulation which you can hide behind a transition effect.