Checkerboard Canyon is a long day canyon. We did it in June 2018. It has a 2:30-4 hour approach. The canyon has changed since the fire that has caused flash flooding and debris to fill up in the middle section. There are several 20-25 foot rappels between rappels 5 and 8 (see KMZ file).
We recommend staying high on the ridge—canyon right—until just before rappel 1. Once there work your way down to the rappel.
We did the canyon with 1 x 220′ rope a 190′ rope and 3 x ~100′ ropes and no wetsuits.
With the 6 miles exit down the Zion Narrows, it took us 11 hours with 7 people and good rope management.