I'm impressed with the amount of work and detail you put into this background. I do see a handful of problems though, everywhere I look on the page I see little corners that weren't filled in all the way, you may want to consider changing the Gap Size settings on the paint bucket tool to Don't Close Gaps.
You may also want to reconsider the tool you use for outlines since the Brush tool is a coloring tool & you seem to have trouble erasing outlines that cross into other outlines. You could erase a lot of those overcrossing outlines using the Line Tool with the Snap to Objects setting on; drag the the Line Tool outline over the affected area, break it and color over the stump you want to erase.
If you want the same visual effect you get with the Brush Tool, it can be done with the Pencil or Line Tool but the only drawback is it takes way longer, but you'll have more refined control of how each color-outline appears.
On the off chance that you're using the Eraser Tool, the Selection Tool is better if you want to delete elements that need to be chucked.
Your work reminds me a lot of a guy's content I enjoy, he's been around since 2004; his username 'round these parts is Noiserover. Be prepared, he has a penchant for disgusting humor.