This blacktop crack filler is available at Home Depot. At first we started off with one small bottle, then we realized we were going to need stock in this stuff. For the second go-round, we went back to Home Depot and opted for the village sized bottle (which we used 100% of), which was only a couple dollars more than the hut sized bottle. When in doubt, always buy extra. Having to stop in the middle of your project is a major buzzkill and derails your momentum.
We poured the crack filler generously over the sand and used a flexible joint knife (the trowel-looking thing to smooth out drywall spackle) to flatten the crack filler, sealing it down. This part was the most fun. It also went the fastest. We moved quickly because this stuff cures in the blink of an eye.