Kochi is 1500kms from mumbai. You could cover Rathnagiri, and through Malvan enter Panaji. Then head to Gokarna, Udupi, mangalore and via Kasargod enter Kerala. Payyanur, kannur, thalassery, Kozhikode, Thrissur, perumbavoor and via ernakulam enter Kochi. On the way there are places like Alibaug, Dapoli, murdeshwar, mahe, nilambur to cover, if you are taking Goa route from mumbai. Another route is via Belgaum that is Lonavala, Satara entering Belgaum route you drive till Tumkur. Then via Bangalore reach Palghat. Then from palghat reach Kochi in 5 hours. Cost depends on the number of days you plan to ride and place of stay.
Awesome thank you so much mam