A cup holder works good for me. A little fabric cooler in the trunk.
A cup with a straw in the cup holder. I can lean forward and take a sip.
In hot weather you need to get off and wet your long sleeve shirt. Fishing shirts work nice.
Keep the sun off as much as possible. I ware an extra large half helmet with a big vizor.
Or get innovative and design something, then share it with us.