Get the fuck in here. Post, rate, bitch, battle, and collect flags.

http://www.serebii.net/omegarubyalphasapphire/secretbaselocations.shtml Locations

http://www.thonky.com/pokemon-omega-ruby-alpha-sapphire/super-secret-bases/ Most of the necessary info

Here are the Blissey bases to start, not only you can get flags off them, but with a level release you can level up pokemon quiet easily.