I recommend putting it in between the pond in the front and the villager house (if you're going to visit Main St. often.), or under the town hall (if you want to go there and to re-tail. You can also go cliff-diving xD).
- - - Post Merge - - -
Or, if you want, you can put it under the plaza (under the river) and place a bridge there. Then you'll really be close to everything.
To the right of city hall. You'll be close to retail and the dock isn't faraway. Add a bridge so you can cross to the event plaza.
Pathway can go straight up to the train station.
There's an indent in the river, just below the town hall. Put one house on the left side and the other on the right. You can but a bridge in between and do some cool landscaping around them.