As someone who had to do the same a few years back, I would suggest two things:
1. Stairs take time and effort. They give a good workout, but I'm already wishing I could have everything on the same level again. Make sure you have phones upstairs and downstairs (it's impossible to move to another floor fast enough to answer it), and a loud doorbell, or you risk not hearing someone knocking if you are upstairs.
2. If you have a garden, figure out ahead of time what you want/are allowed to do with it. Lawns and plants need maintenance. A patio would be more convenient if there are no children involved.