Alternatively, you can glitch your way down from the bee area to the shores and plains areas if you solve an (unintentional) jumping puzzle and are patient. Then you can activate the quests in those areas to get the necessary keys to finish everything off.
The basic idea is to start at the stone bridge leading from the plains to the jungle neko area (preferably grabbing the respawn stone here for when you fuck up).
- Turn to face the hill while at the top of the stairs (i.e. the direction of the ranch), and note that a few well placed jumps can get you on top of the stone columns. One jump to the rock, a second to a higher rock, then a third to the column.
- From there, you go over the mountain (toward the ranch) or around the right side by jumping around and down the geography, being careful not to fall too far or slide of the edge.
- The shores are actually easier to get down to (going around the right side) as there is no invisible wall on this path. In contrast, getting to the plains requires you to go all the way around to the gate (where the wall invisible wall ends just short of the door). It isn't trivial, but it isn't speedrun difficulty either, and I have done it 3 different times for different release builds to avoid disappointing slime waifu and to unlock certain nephs/traits early.
- Once you are done exploring the new areas and collecting missions, just save and reload to return to the ranch, or if you have already unlocked the desert, you can just open the portal in that area instead.
TLDR - Just skyrim your way over the geography to break the fucky progression system.