the place is located 40 minutes northwest by car from the Fjordstadt Førde

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"just" means "nur", "ca." would be "some" or "about". "40 minutes' drive" (while plenty of people drop the apostrophe these days I think it's worth keeping)

"The place is located some 40 minutes' drive north-west of Førde."

X is about 40 minutes by car from ...
By car, X is about 40 minutes from ...
X is about a 40-minute drive from ...

I agree with Phillipp about the apostrophe before a second noun:

X is about 40 minutes' drive from (the fjord city of) Førde.

I would also prefer 'fjord' (Scandinavian) over 'forth' (Scottish). However, 'fjord city' doesn't really sound very English; a better solution might be something like 'the city of Førde, known for its fjords,' or if it's about the etymology, 'Førde ('fjord city').'

Sorry, forgot the direction part, which does make things a bit more awkward.

X is about 40 minutes northwest of Førde by car.
By car, X is about 40 minutes northwest of Førde.
X is about a 40-minute drive northwest of Førde.
X is about 40 minutes northwest of (the fjord city of) Førde.

To my ears, the 'by car' or 'drive' parts aren't really necessary, as we tend to assume that distances given in minutes imply driving. That is, driving is the default method of transportation; if you were giving other times by, say, foot or bicycle, it would be more necessary to mention those specifically.

Welcome back, dotcomrade hm -- us ;-)