I'm attempting to thrash out a point in a story idea I'm dealing with, and I could use some assistance. Where is there in Ponyville that a pegasus could hide where a changeling would be exceedingly unlikely to find said pegasus?

3440926
Pegasus-specific? Considering that changelings fly, it is extremely unlikely that 'up' will be an obstacle for detection.
What do you say underwater? Inside the mud baths at the spa? Inside the bog at Froggy Bottom?

taking fluttershy's idea, how about a tree...
in the center of a hollowed out cloud...
if the pegasus is called surprise, any where by being a pegasus pinkiepie...
underneath town hall, (the area that dash ended up in when derpy trashed town hall in "the last round up")...
sweet apple acres barn/any where in that orchard especially in bales of hay or cmc club house...
depending on the colour of the pony anywhere could be a possibility depending on season as well, for example, light green-feild in late spring, dark green-white tailwoods/everfree/bushes and trees, golden brown- whear field in late summer mid fall, white-snow, sky blue- flax feild in late summer early fall, the list is neer endless...
could probably write a report with the roll i just got on so im gonna cut off here...

3440926 Hidding from a changeling is easy. Not like hiding from Pinkie Pie would be.