I recently discovered that small to medium worlds perform well on my laptop, and I would like to try my hand at making something similar for myself. However, I don't wish to create an island to hide the borders of the smaller map.

I was wondering if a) using a large map size and using camera/routing paint to create a smaller playable area (and design to match) would cause a dip in performance, and b) if there were other options for distant terrain besides using a larger map size.

A large map needs to be rendered, even if it is mostly empty. The camera/routing paint doesn't help with that. But of course a large map with only a few lots will run better than a large map with plenty of lots. Not as well as a small map though.

That said, you can use tools to resize existing distant terrains like any other object so they would fit a smaller map. It might look funny though, as the illusion of a large land mass in the background will fade with a small distant terrain.

There are also EA maps in different sizes. You could use the university world as a template if it fits your world ideas, it is "only" 1536x1536 instead the regular 2048x2048 of most EA maps. For comparison, a small map is 512x512 and a medium map 1024x1024.

There are also a few custom distant terrains out there, some of them even for smaller worlds: https://hydrangeachainsaw.tumblr.co...stant-terrain-1

And of course you can create you own distant terrain: https://hydrangeachainsaw.tumblr.co...errain-tutorial

In the first world I did I just sculpted the land in hills high enough that it worked like distant terrain and with the camera routing worked perfectly well.