One of the things I keep running into when editing lots into a world in-game is that, many times, new lots you've added don't snap exactly to roads, or are branched off in a weird way because of routing issues. Thus, if there's grass terrain, there's a green line left between the road and the lot. It's annoying, especially if you're adding onto a city into an existing world.

What I'm looking for is if it's possible to paint the terrain without using CAW. I know in CAW you can edit terrains, but for that you need to actually have the world files. I've gone and pondered creating a world 'rug' that can be placed underneath lots, but my attempts haven't produced much.

I hope this is in the correct place! This is sort of a weird question.

I don't find the question odd at all.

It's something that annoys me too (on the premade worlds), but I don't think there is anything you can do about it.

Manually editing terrain paint files, if even possible for an extracted world, should be a tedious job. You can't terrain paint world in the game editor. Only option I see is to open the world in CAW and do the edits there, and this too only when you just want to change something permanently (the process is easyish, but requires some effort).

You can edit/redo an existing world by getting your hands on the CAW files, making the changes, and then doing a new export. We have a very nice tut for editing premade worlds here: http://www.modthesims.info/showthread.php?t=469942

Thanks for the link! I've always appreciated the tutorials on this site.