Which keyboard dock would I have to buy for this?
Does this come with a keyboard?
No, the keyboard shown in the sales pics are optional
The Microsoft Surface Touch Cover Keyboard for Surface 2 appears to be the proprietary keyboard for the surface but other options are available.
Isn’t 8.1 RT being dropped from support by MS?
Microsoft is no longer making devices with Windows RT but they haven’t announced that they are discontinuing support. There are still a lot of early Surface tablets out there.
As a comparison, they’ve only just recently discontinued XP support.