The route from Trin to Platt 'Alva has it all. At first a very nice new tarred road, because you get along really well. Later Kiestrasse, in the end really steep. Total 1200 meters in one piece, because you have to go through. The glacier mills on the Alp Mora but worth the effort!
If the weather is hot (today 33 degrees Celsius) I would go really early, then you often have shade. 7am from Trin or a little earlier. In addition, you'll have the glacier mills on Alp Mora for you alone.