Astronomy detail for my short story

Hi all, I'm trying to write a short sci-fi story and I want to get some
detail's right. I need to know roughly the distance in light years, from
earth to the edge of the heilopause or just outside the sun's gravity
well. It doesn't have to be exact, + or - a few million K's is alright
and the direction would be the southern hemisphere towards Alpha
Centauri, again + or - is alright.

And if someone knows the time it take light to reach the planets from
Mars onwards would be great or if you know a web site with the times.

One more thing, how fast can you go at the speed of light so you don't
incur time dilation, 80%, 50% so on.

Thank you and clear skies to you all.

Dario.