I present a YUGE Worldpainter project that i have worked on for the past 2 weekends,
The land is 14,000,000 blocks,

The Island of Oriana (Island of Gold, if you will)

You spawn in Hotland (Undertale Inspired (Obviously)) a massive desert biome, but just to the north,

The Island has a massive deciduous forest (The Forest of Dissonantia). To the north of that, a yuge snowy taiga biome, and to the north of THAT, some snow plains(Plains of Isolde).

The northwest contains the Mushroom Zone,(NOTE: No Mushrooms, Sorry!) a land plagued by the spores of erratic fungus, just far away enough to not infect the main island.

To the east you find the Mountain Range (Mountains of Thanatos), and directly south of that you find some regular ol' plains.