Since the bus drops at Madikeri, plan a stay at Madikeri for 1 or 2 night. Sight seeing places like Rajas seat , raja tomb, Madikeri fort, Abbi falls are very near from Madikeri bus stop. You can walk to rajas seat around 1km only. you can cover all these Madikeri sightseeing by auto also. there is auto stand nearby Madikeri bus stand. Above Madikeri sightseeing can be done in half day. Buses to Bhagmandala and Talacauvery also available from Madikeri bus stand. so 1 day you can cover Bhagmandala and Talacauvery . You can visit kushalnagar around 30 kms from Madikeri via bus or hire car. place to cover near kushalnagar are Dubare elephant camp, Nisargdham, Tibetan monastery, Harangi dam.
this can be done in a day. so visit Madikeri back if you are planning to return back from coorg directly