Want to make some serious adena from killing mobs, go to monastery of silence and see how many bots are running their bot apps. If you get a chance to kill elite mobs they drop around 20 to 30k + adena depending on your level. Whilst making your way there count how many summoners you will see.
Not only will you make adena from the mob drop, but the recipes and other material drops reach a good price. And if you take the quest middle floor you will make even more more more.
Once again, if you can get through Bot's there you just and i mean just might make some good coin. Hopefully the GM's can pick this up and start cleaning some areas that are overtaken by bots.
It's the same for many pre-GoD high level party areas: MoS, HB, DV, DVC, etc. Adena drops are very good if you're 85+, but exp isn't and you can get the same value in adena/items per hour and more if you do daily instances and quests with multiple 85+ characters instead of hunting in those pre-GoD areas. These areas are mostly used (and are usually crowded with) the 'you know who' players who hunt there all the time.