So, you've decided that you're going to make the move to a single device which can do everything and free yourself from the tyranny of multiple machines, complex workflows and relying on cloud services for synchronisation.
It's a good plan and, depending on which machine you choose to do this you'll need to get things setup in rather different ways. In either case the goal is to minimise the amount of time you spend on other devices as close to zero as possible.
Starting with the iPad Pro. For starters you'll need to decide how you're going to use the iPad.
If the iPad will be used on your lap you can throw away Apple's keyboard case and search out an alternative which makes the iPad more stable in your lap. In my experience the Brydge Keybord is the best option here.
If you're planning on using the iPad on your desk you'll need a Bluetooth keyboard and one of the available Lightning to display adapters. The iPad's display can then be mirrored to a bigger screen, which will save your eyes, at the expense of your arms, as you'll still need to reach out and prod the screen for most tasks.
Finally if you're going to be using the iPad as a pure tablet you've nothing more to add.
Having established what hardware you'll need the next step is to look at what tasks you're planning on moving to the iPad. Is the software you use available for the iPad? Is there a third-party alternative. Does either work well enough to replace the tool you're currently using? Do you have the connectivity to peripherals you need?
To use a Surface Pro as your primary computer follow these three steps. Step one, turn it on. Step two, plug standard peripherals in. Step three? To borrow a line from an Apple ad, there is no step three.