If we are sharing levels, here are two I made:
Fly High Against the Airships: 9DD1-0000-0030-EDBC
Ashley's Haunted Micro Games: 7B99-0000-0039-D956
Put a lot of effort into making these. The first one has two paths to chose from, (though you need to figure out how to get to the upper one, though it is pretty easy to figure out if you know your Mario). The upper path features more rewards (like one ups), a hard middle section, but a way to avoid the final obstacle standing.
The bottom path is generally easy with just hard boss encounters.
As for Ashley's Haunted Micro Games, while there aren't any alternate paths, took a lot of time to make the "Micro Games" play out how I wanted them to. I actually reached the limit of placeable blocks for the sublevels.