After activating Little Glass Butte, I drove down the south side towards Round Top Butte (GPX). The road down was rocky with obsidian, be sure to collect some when you stop to open the wire gates. Once down the mountain, turn east and follow the ranch road. I parked at approximate 43.50076, -119.93735. From here head into the brush (GPX). Eventually you can find an old overgrown firebreak carved into the hillside. This is what I followed to the summit. It is overgrown with brush, but the brush is slighly shorter than the surrounding slopes.
The firebreak goes up the mountain to the first saddle, then up to the main summit. On satellite imagery you can actually trace it down the other side of the mountain.
The actual summit is unremarkable and mostly barren. I set up in the shade of a small tree. It was late Sunday afternoon, but I managed nine QSOs on 40m and 20m thanks to the NA-SOTA Slack. Once packed up, I followed the firebreak back down the mountain to my truck. I drove a few minutes farther east and found a nice spot by some a couple trees to camp for the night.