miles and miles
A considerable distance; also, a large interval, by far. For example, We drove for miles and miles before we saw a gas station, or She was miles and miles a better pianist than her brother: This usage was first recorded in 1889.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.