Greetings Machine God,
Ah, there's nothing I enjoy more than the flimflammery of sci fi physics... so let's get started.
Here we're talking about the Mandeville Point, which is the sweet spot where a starship enters or exits from warp space. This isn't necessarily on a system's edge. It's just a clear area between gravity fields in system so as not to mess with cogitator calculations, damage/destroy the ship, and far enough from populated areas so that they are safe from contamination by warp juice from the warp hole.
Now time to target is going to be based on a number of factors, including mass of the ship, momentum coming out of the warp rift, time to fussion engine start. Thrust power and ratio of the engines, how long it takes to accelerate to maximum speed (let's say 1/4 light speed), how long it maintains max speed, deceleration time to target, etc....... still with me on this.
Once you've got your engines started, you figure it will take maybe a day to accelerate to max speed ( you don't want to be going accelerating so fast as to blowout the gravity dampeners and turn the crew into people paste). So depending on distance to target, could be as short as a day or a week or more.
So those are some things to keep in mind. For an example, Dan Abnett has a good description in ' Know No Fear'. The ship doesn't bother with the deceleration part as it's there to misbehave. It will give you a good idea of the time involved though.
Hope that was of some help.
Edited by Brother Lunkhead, 16 April 2020 - 05:43 AM.