Note, there is a new trail [just built] to Mason Lakes. The new trail is the same distance as the old trail (~2.5 miles) and starts from the same trailhead. It leads more over to Bandera Mountain then contours back toward the old trail at the saddle between Defiance and Bandera. The new trail is very nice. I took the old trail on the way down and I can definitely aver that the new trail is the way to go. The old trail is not recommended. It is heavily windfallen, rooted, and needlessly crosses a bothersome boulder field. You might make a note of this new trail on the main page and/or on your "Mason Lakes #1038 Approach" route page.
The old Mason Creek trail is in good shape, saves 1.1 miles and 135' elevation gain each way, and stays left of the boulder field.
I took it last Wed after work, and it's in great shape--better than I remembered from eight years ago. It stays in the shade until the final traverse near the summit trail. If you get to a place where you are heading right onto the boulder field, look for the trail to the left. Mason Lake is already nice for swimming this season.
The Here's a recent nwhikers TR about the trail.
Thanks very much for the update.