We are adding float fishing (bobber fishing) with the upcoming fishing mechanic update. In the version that is being developed, you will be able to set the depth of your bait which will give similar gameplay as bait fishing (bottom rod).
Drive-able boats are harder to achieve since the devices have limited computing power, so realistically it will not be possible.
The way we develop maps is by going to a specific location that fits the criteria with highly specialized equipment to take a photo. While some of us in the team love adventures, I don't think it will be in the near future we will go to the Amazon Rainforest :( We are planning on adding US West this year (December) and US East (1st half of next year) as DLCs. Then Japan OR SEA in the 2nd half of next year.