Can I set up everything before I actually need a walk/ visit?

First thing I would do is to set up your Rover profile and add any pets you own. Even if you don't have exact dates you can begin to search for Rover sitters who live close to you to find a few you might like to meet with to care for your pets. You can communicate with any potential sitters by creating a booking request, and then setup a time to meet with them, and them with you to see if it is a good fit. Best of luck