word order

08:04 Sep 1, 2016 

In general, I would use "the Öreälvsleden trail".
Reasoning:
(1) The name of the trail is "Öreälvsleden", not "Öreälv".
(2) An English-speaking person cannot be assumed to understand that "led" means "trail".

Imagine an imaginary country with a trail called "Colaponaqui" or something like that. You would refer to it as "the Colaponaqui trail". It might turn out that "aqui" is an ending, or the second part of a composite noun, meaning "trail", but that probably would not make you change your translation to "the Colapon trail".

The above reasoning would apply to any entity for which there is not already any alternative English name established.

It could for instance happen that the tourism agency of Öreälv would begin to refer to the trail as "the Öreälv trail" in various brochures and that this would become established usage. In that case, "the Öreälv trail" would effectively become a name for the trail in English and it would then be correct to use this name when referring to the trail in translations. In that case, a suitable translation could be "the Öreälv trail (Öreälvsleden)" at the first instance of the name in the text.