Doc is quite literally beaming in panel one.  Giving off his own light as compared to reflecting the sun’s rays, as it were…

Mark is maintaining his poker face…  The rear 3/4 view that we are all familiar with from the Trailverse clip art catalogue… Leola completes the picture.

Regarding comments about what the other Trails are doing back at the ranch…  Remember Mark and crew (despite the months it feels like) have been gone only a few days now.  Not that hijinx couldn’t already be ensuing or carnal desires sated, but if so, the family would be moving on that fairly quickly…