Q.spring pruning winter damage of rhododendron
This winter was unusually cold and deep snow. The one nearest the road appears to have suffered the most and has a significant amount of dead leaves. Is it better to trim the dead area now, or wait until the fall?

I would go ahead and prune the dead or damaged areas of your rhododendron now.
Here are some articles that will help you:
Pruning winter damaged shrubs:
https://www.gardeningknowhow.com/ornamental/trees/tgen/winter-damaged-trees-shrubs.htm
How to prune rhododendrons:
https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/pruning-rhododendrons.htm