Also, it might be a performance issue rather than a walking speed issue, have you tried turning down the quality settings? You can find them by pressing esc and going to the options menu.

I think you might want to look into using some sort of scrolling world instead of making your world just really long. It would make for nice and smooth scrolling, and probably also some performance increase as well!

I haven't found any issues yet, so it should be totally fine to use! If you find any bugs be sure to let me know! And just so you know, the Load function has been changed, so check it out :)