Hi, watch the video while reading this to get the best view on what I mean and how to do this.

In the "Camp" there is a bridge and a structure direction east. You can't get there intentionally if you haven't progressed enough. (I did not check this but I guess it is meant to be unlocked that way) First you glitch to the other side of the fence to get the allignment. After you have aligned you precisely position yourself to the edge of the block, after that you position yourself for the roll, you do this with a bow. Then you use the "Boots of swiftness" and the "Dash Roll". (with the "Death Cap Mushroom" added it is easier") at the exact same time you will roll onto the other side of the bridge and explore an area that is not meant to be explored yet. 

In the video I also show how to get a 1 time chest and to get out of bounds again. This is not meant for this report.

Video I am reffereing to:
https://www.youtube.com/watch?v=8M8uLrRZVJE&feature=youtu.be

-Video more then 10MB, uploaded to YouTube