I have stuff spread out all over the place. For photos, I use iCloud, because it synchronizes between my tablet, phone, and laptop.
For other documents, I usually leave them parked in the app that created them and let iOS back them up to my iCloud account. I have some of stuff parked in Dropbox.
I use a Logitech Bluetooth keyboard that syncs with three devices. I take it with me to the office each day so that I can easily switch between the MacBook Pro and the iPad Pro.
With my earlier iPads, i was using a keyboard case, but they just felt like they added too much to the tablet. I've decided that I like the separate keyboard.