Valley of Fire is open sunrise to sunset. You need to be in or near your vehicle by sunset. An entrance fee of $8 for Nevada residents or $10 for non-residents is required.
This isn't so much a trail as a short path out to the photo op at Balanced Rock. They've brought in crushed limestone for this trail, which is different from the other sandy trails in the park.
The trail allows you to get up close and personal with one of the rock formations, but there are better trails in the park if you've got a little time, and it's not too hot. As close as this is to the visitor center though, it's hard not to check it out.