Kota to Mumbai is a distance of 942 km and time duration of this trip is approx 18 hours. You can find many places to have overnight stay on this route like Vadodara, Bharuch, Surat, Udaipur, Indore, Nashik.

You will be able to see some huge rivers on this route and major ones are Narmada, Godavari and Tapi. There are scenic bridges, ancient temples, cities that are built on these rivers and major ones are Surat on Tapi River, Bharuch on Narmada River, Nashik on Godavari River.

This route passes through green forests, lakes, mountainous regions, and you should keep a look out for heritage monuments, famous temples, forts, lakes, artificial reservoirs, dams, wildlife sanctuaries, waterfalls, river bridges that come on this routes. The best routes to reach Mumbai are:

Route 1 (929 km): Kota > Indore > Dhule > Nashik > Mumbai.
On route attractions: Gagron Fort, Mahakalshwar Jyotirlinga Temple (Ujjain), Lal Bagh Palace (Indore), Maheshwar Fort, Nashik-Trimbak, Igatpuri,

Route 2 (959 km): Kota > Neemuch > Mandsaur > Godhra > Vadodara > Bharuch > Navsari > Vapi > Mumbai.
On route attractions: Pashupatinath Temple (Mandsaur), Kadeliya Dam (Banswara), Champaner-Pavagadh Archeological Park, Vadodara sightseeing, Narmada Park (Bharuch), Tithal Beach (Valsad), Daman, Silvassa, Tungareshwar National Park.

Route 3 (1034 km): Kota > Chittorgarh > Udaipur > Modasa > Godhra > Vadodara > Bharuch > Navsari > Vapi > Mumbai.
On route attractions: Chittor Fort, Udaipur sightseeing, Shamlaji Temple.

On route travel tips: Vapi comes on this route and Daman and Silvassa are just 1 hour drive from Vapi. Bharuch also is full of ancient temples and natural scenery. Champaner-Pavagadh Archeological Park is close to Vadodara and you can see age old monuments here.

You can also visit Ajwa Lake in Vadodara. Indore and Ujjain are very cl0se to each other and you can do side trips to Maheshwar which has some very find river ghats on Narmada River and you can even do boating in Maheshwar.