Hey, I found a website to calculate how long it would take to travel "in system" using conventional engines. It even has the time to get "100 diameters" from an earth-sized body as well as small and large gas giants.
Find the link
Here is a new OSR sandbox-style post apocalyptic game that caught my eye today. Have a look at this review at Grognardia and comment on whether it would be of any interest to play.