Definitely some good ideas for creating a story in here. Execution needs work, but it seems like a good starting point.

There was enough new and unusual material to keep me reading, and I wouldn't mind seeing where else this goes.

Criticisms:

Body mapping scene doesn't ring true. It's a common issue for self inserts in the ponyverse.

- Everyone has a mental map, created by experience, of what muscles will move which body parts to a given position. The pony body just doesn't fit. A hoof is not a hand, it's more like a fingertip. There are several joints right near the end of the leg. MLP forelegs are more complex than a natural horse, as we see them bend, swivel, twist, and wrap in a variety of ways. The neck is another huge difference. Able to twist around completely, attached to a different part of the skull, etc. The head itself is going to be an experience. New span of vision, odd new ear muscles, breathing in with BIG nostrils, and the lips which are good enough to write, hold, and manipulate tools. Just saying you have four legs seems inadequate.

Grammar/spelling issues. Happens to everyone when they write, but annoying when you read it.

"bad that in can go." - "bat that it can go."

"as the wagon somehow to an extremely sharp corner" - "as the wagon somehow turned to an extremeley sharp corner"

Descriptions are really minimal. If the reader knows Equestria it can work out, but descriptions can add a mood to the scene as well.

Consider:

A talking purple unicorn with a female voice.

- A casual and intellectual female voice came from the purple unicorn.

- Hearing and rationality clashed when the lips of the horned horse moved, and I heard a melodious girl's voice.

- A sympathetic female voice calmed my ears as the unicorn _talked_.

When someone like Twilight tells a puzzled and lost individual where they are, she would try to be helpful by adding details. "South side of Ponyville near Belleblossom fields." perhaps. Just saying 'Ponyville' wouldn't really tell a lost traveler very much.

I'd suggest 'nibbling on loco-weed' or 'eating fermented apples'. Rotten/Bad apples might make you sick, but don't usually cause mental confusion.

Changing voice from personal, to external to another pony seems to occur in several places without warning. This is not a good thing.