I understand why you have a weird feeling about franchir.

It can be used in both way:
– In your case, It just mean you go from point A to point B through something.
– Your other guess is right as well. Franchir could imply that you worked hard to do it. After a marathon, you can say : “le coureur a franchi la ligne d’arrivée”.

To be short, both meanings are right so your sentence doesn’t sound weird.