Luckily, rhododendron are a species that will regenerate growth on old wood. Pruning will encourage this however I would not recommend pruning the first season it has been moved. Next season I would look at pruning to get more sunlight to bare areas either by thinning or reducing the size of the canopy.

If you are planning on a drastic pruning, 20% or more of the canopy, I would wait until the dormant season. Although you will loose some blossoms the first season following the pruning, proper timing will pay off down the road.

Always prune rhododendrons immediately after the bloom is finished to avoid removing buds and to get new buds after you prune. A light pruning of the top will stimulate the bottom to start opening adventitious buds under the bark that you can't see.

Here is a link that might be useful: How to grow rhododendrons and azaleas.

My little rhodie didn't bloom this year (I accidentally pruned it in July last year- my first month in the house and my first rhodie). It is exhuberantly healthy- just not a blossom in sight. Do I prune/shape it now, after the blossoms SHOULD have appeared, or do I wait til the fall?
Thanks

If you pruned last year and its young, it shouldn't require pruning....shouldn't require it most years. And never in Fall or you will be removing the flower buds for the next Springs blooms - those buds are set in summer.

If you wish to shape your young rhododendron into a more densely branched form, selectively pinch out some of the growth/foliage buds with your fingers as they begin to elongate and open (so a Spring chore) - no cutting necessary.

Why not enhance the tree look rather than the bush look? After all, it's going to get bigger all the time.

Here's one that was planted too close to the driveway thirty years ago.
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I can see through it now.