Welcome back.
Definitely go to Arcadia, it's far busier than p69.
If creating a new character in Arcadia, this is different advice I would give to a properly new player, but since you clearly have good experience of Mir so you want to get a good start... run to BW and ask (nicely) for someone to give you 100k gold (this is nothing to any high level player), if I'm online at the time I will help you out. Go to the Farmer NPC just east of BW SZ and he gives you a lot of quests, complete the "Money Problems" quest, all you need to do is give him 100k (that's what the money was for!) and the exp reward will boost you from level 1 to approximately level 55. Then find a group of friendly players who don't mind you tagging along on group hunts for a bit, until you're about level 100 or 110. That really shouldn't take long, a day or two at most. Pick up food items and other bits and pieces along the way that drop if the group doesn't mind (most people leave them on the floor, you can fill your bag and sell for between 10k to 50k each) Then you can start looking out for kit, don't spend a lot at this stage, but check auction house (blue button with white icon near the bottom right of your screen). Once you have level appropriate kit and start to learn your way around, you'll be able to complete some of the other farmer quests which will give you good exp without having to kill too much. Then aim to kill level appropriate bosses and blue/red mobs to gain 'game points', lots of game points are required as payment to enter some of the higher level caves where most people do big guild hunts etc. and game points cannot be traded.
That advice kinda covers all classes, but once you reach that point let us know your class and we can give you further advice. I can talk all day about wizards, but for other classes you'll probably get better advice from people who play those classes more.
