Naturally, we established a difficult but possible trail to see if indeed you could do it.

The more difficult trail is the only way to see some features such as the dwarf forest.

Instinctively and from long practice he made his trail difficult if not impossible to follow.

It had been a long and difficult trail.

From there the party pursued the natives "for ten or twelve days, the most difficult trail I even followed."

This is the longest and most difficult trail at 26 miles long.

Follow the 1 mile difficult trail to the falls.

Admittedly the most difficult and technical trail in the park.

His pride increased at negotiating such a difficult trail to keep ahead of the rest of the children.

Why would they take such a difficult trail?