You can use Stellarium (
https://stellarium.org/) to easily find the distance between two bodies and their positions at a specific date/time.
Set the date with F5
Select your observation location with F6 (planet, moon, ...)
Hide the ground with G
Find and select another location with F3.
Among the data show on the left will be the distance from the observer to the target (in AU and km).
By selecting the observer location as observer of solar system, centering the view on the sun, and adding the orbits, you will get a nice planet location map for any given date/time
You can much more, obviously, it is an amazing tool.
Edit : even easier, there is a distance tool between 2 items (using F10)