Are there gaps between Saturn's rings? What is the shortest gap? What is the longest?
Yes, there are many divisions and gaps.
The Cassini Division is a 4,700-km wide gap, between Saturn's A Ring and B Ring. This one is the widest.
The Huygens Gap is a 285-400-km wide gap located at the inner edge of the Cassini Division. There are other gaps within the Cassini Division, but the Huygens Gap is the widest.
The Kuiper Gap is a 3-km wide gap within the Cassini Division. This one is the shortest.
The Encke Gap is a 325-km wide gap within the A Ring.
The Keeler Gap is a 35-km wide gap within the A Ring.
The Roche Division is a 2,600-km separation between the A Ring and the F Ring.
The Maxwell Gap is a 270-km wide gap within the C-Ring. There are other gaps within the C Ring, but the Maxwell Gap is the widest.