Without warp drive, it will take 17 years, 2 months, and 3 days to reach the nearest Federation starbase from "deep in Cardassian space" in "Time to Stand."
"The Valiant" - Nog and Jake drop to impulse to fight Jem'Hadar fighters in order to gain an advantage in maneuverability.
In "Emissary," we see mass-lightening fields at work in an ad hoc impulse drive used to propel DS9. The subspace field increases acceleration by a factor of 2,600-230,000.
Ordinarily, the six working thrusters would bring DS9 to a position 160 million kilometers away in two months; by using a subspace field, this time can be cut substantially - to between 3 and 28 hours. (O'Brien's first stated ETA is 3 hours to the wormhole; the Enterprise, originally stated to be 2 days away, is still 20 hours away when the Cardassians attack DS9 at the wormhole.)
For a fly-by intercept, the average accelerations given would then be 1.2 cm/s2 and then 31-2740 m/s2; for a zero-zero intercept (necessary given the relatively stationary wormhole), the accelerations are 2.4 cm/s2 and then 63-5500 m/s2.