Exit Yeshvantapur Bus stand from the end of PF-6 and take any bus that comes there aand get down at Yeshvantapur bus stand. From there move to the lower deck of the bus stand from where you can take K2 to Satellite bus stand
From Satellite bus stand you will get non stop Express buses (Ordinary) to Mysore every 15 mins once with a break in between-Fare around Rs. 130/-. Regular Deluxe (Rajahamsa) (Fare Rs. 200/-) and Volvo services (Fare Rs. 250/-) too available. Apart from there buses bound to MAdikeri, Calicut, Thrissur, mangalore via Mysore will also be available for your journey
Or...
more... else from Pf-6 side take 252 or 258C or various other buses to Majestic and walk to City station from where Chamundi Express leaves at 1815 to Mysore. This is followed by a passenger to Mysore at 7PM.