I've worked a bit more on the exact itinerary and managed to shorten it by 30 minutes.
It's easy on Google Maps to create a loop between 2 points while following these 2 constraints:
* minimising the time to travel,
* using a different path from the way-in travel.
Here is a quick and easy solution:
Step 1 - Get directions from point A to B: the shortest one gets highlighted.
Step 2 - Assuming the second shortest path is sufficiently different from the first one, choose it for your way back to point A.
Example from Bangalore to Udupi:
