Bangalore has been surrounded by plenty of beautiful places covering up from hills to beaches (around 350km).
My first suggestion would be The Heritage city MYSORE
Its 3 hour drive from Bangalore. You have best restaurants in Bangalore-Mysore highway. If the option of Mysore is ruled out then here goes the other list.
Bisle Ghat: 246km far from Bangalore. One can see the Mountain view of 3 districts i.e Kumara Parvatha of Dakshina Kannada district, Pushpagiri and Dodda Betta of Kodagu district and Patta Betta and Enni Kallu of Hassan district.
Roads are not too good but enjoyable. There is no stay and food available. Its a remote place and hence care should be taken. It lies in the forest region of Kukke.
View from Bisle view point…
Mallali water falls : 28km from Bisle ghat.
Kukke subramanya temple : If you wish to visit the temple, its one of the good place. Food is served at temple and you can see devotees all around. Pretty good accommodations are available. After covering the Bisle ghat and Mallali falls one can plan for the halt in this town.
Now after a day trip you can head back to Bangalore covering the places below
Manjarabad fort : 44 km from Bisle, this fort attracts a huge number of tourist. It is the Star shaped fort.And here is the aerial image of it.
Belur and Halebidu