Here's an example of four-way scrolling using 32x32 tiles :
The black rectangle is your drawing window, the top left of which is what's written to Suzy's scrolling / offset registers.
Each red square is an individual 32x32 sprite, the letters on them represent unique SCBs. There's a large border around the drawing window so we can scroll smoothly.
We've started scrolling right just by modifying Suzy's scrolling registers and performing the draw again. There's nothing to recalculate until...
...we hit the border on our right. Then we'll shift over the x-position of our left column of SCBs and assign them new textures.
Again, this is just one way to handle a large playfield. Whatever is best for your project's requirements is what you should use.
Linking all the SCBs used to draw the tile background together rather than drawing each individually will improve performance. Generally, you want to minimize the number of times Mikey has to tell Suzy to draw sprites.
You also want to minimize the amount of data Suzy has to fetch. In the scrolling example above all tiles are the same size, so we don't need to have Suzy reload the scaling field on each SCB. It's actually faster to draw a dummy "prefix" SCB which just sets the scaling values to $0100,$0100 before the background. If you can chain palettes that's even better.