From mumbai if your are planning bike trip to south India Via Bangalore you could drive to Munnar Kerala
Via Bangalore travel towards Coorg Karnataka Via chennai you can visit Pondicherry Tamilnadu Via Bangalore travel to lambasinghi Andhra Pradesh Travel on road is for long hours, but views are good, picturesque and there are lot of places you could take a break from the journey. If you are planning towards Goa, it’s a 11hour journey where via Panvel, Lonavala Belgaum reaching Goa is easy. Travel time on road is short and you could halt at Kolhapur. With onset of summer, I would personally suggest driving to Goa is lot better than travelling to south India. For south India will be as scorching as Goa. You could plan a travel to south India especially Kerala and Karnataka after June based on the monsoons.