Why dont you see Chigmaglur,240 Km's from Bengaluru. Its a beautiful place.
Chikmagalur | Chickamangalur | Kemmangundi | History of Coffee - Karnataka.com
Chikmagalur Tourism - Chikmagalur Travel Guide - Chikmagalur, Karnataka, India
If u want to go Kovalam easy way ,first catch the Indigo flight non stop till Coimbatore you will reach at 4.20, if you want to reach little late catch Spicejet reach at 7.40 pm. there are many trains from Coimbatore going Trivandrum. Train no .2695 is best it is at 11.00 pm and you will reach Trivandrum at 7.30 Am .
Other sight seeings are
1.Allepey
2.Cochin
3.Kanniyakumari (1 hrs from Trivandrum) 4 to 5 Trains available better catch Cab.
If any information u need ask me I have visited Kannyakumari 3 Times and Trivandrum once.
sight Seeings in Trivandrum
1.from station 10 Kms away is kovalam Beach very good.
2.you can go shopping,lots of showroom are there.
do not cancel your trip to Kovalam it is a very good place.
near beach just 1 km walk is a place I dont know the name correctly .It is actually like houses they give the rooms for the lease and rent.We stayed there and the all beds,
ac,
fridge,kitchen were provided .Last day after completion I dont want to return back to my Home I liked Kerala so much.I am planning to go back in Januray Once again to same Home.
Night Trains
2695 Trivandrum (Coimbatore at 11.00 pm Daily Train)
6381 Trivandrum (Coimbatore at 12.00 am Daily)
there are many more trains but 2695 is superfast and one more thing is that in early morning u can enjoy from train by seeing lots of back water lakes on your both side and this train has very limited stops.