Effortless progress, as in It's easy sledding from here on. This expression alludes to coasting smoothly down a hill and was first recorded as smooth sledding in 1898. Also see the antonym tough sledding.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.