Karnataka in Monsoon
There are a number of destinations that can be visited in Monsoon.
Coastal Karnataka - It rains a lot on monsoon but drives get that much green and beautiful. Jog Falls which is roughly mid-way on the Mangalore - Goa route comes to life during monsoon. So Jog falls combined with some idyllic beaches and temples (Mookambika, Murudeshwar, Udupi Krishna Temple etc.) make for an excellent driving break (3-6 nights).
Coorg - Coorg is a coffee plantation country and so its supposed to rain persistently but it rarely rains beyond what one can take. Rains here are enjoyable for those who do not arrive with a fixed plan and aren't too short on time. Its also a good time for those who wish to enjoy bargain prices at luxury resorts. As its any case raining on and off all the time, a segment of guests arrive to relax, rejuvenate and indulge in luxuries and amenities that these resorts offer.
Nagarhole - Nagarhole (Generic Name for Rajiv Gandhi Wildlife Sanctuary) lies between Enjoyable Rain option of Coorg and heavy rain option of Wayanad and still it does not rain too much here and park unlike ones in Madhya Pradesh are open for Safaris. Nagarhole has several luxury lodge options and though from the point of view of Bird watching and wildlife its not the best season, but the terrain and over experience when combined with Coorg still makes for a good idea.