Actually, colors in the alpine regions are just starting to show themselves. But it won't be long as colder temperatures settle in. Daytime temps are still great for shorts and t-shirts; come prepared with some warmer layers. Up high -- 9,000 feet plus over Tioga Pass and into the Lakes Basin -- skies are blue and that Sierra Nevada sun can be intense. Sunglasses, sun screen, hats, and plenty of water is the rule of thumb.
Lakeside strolls, fishing, and hiking couldn't be better. Check ahead about campsites. There were some available sites mid-week but weekends are always a different story.
Coming from Lee Vining or Groveland, get an early start and enjoy the journey. Slow and steady is always a good mantra. With plenty of parking at favorite lookouts, you won't have any trouble. High County meadows are wearing their late autumn gold. And a little wading along the shorelines of Tioga or Tenaya lakes. While distances from one side to the other may seem minimal, this is the ultimtate long and winding road. Speed limits are reduced with good reason. Lots of beautiful vistas also mean lots of drop offs.
Pack food since many services on Tioga Pass have already shut down for the season. Of course, use caution regarding bears and provisions.