If you're in trouble to see how to drive a reasonable time in Z95, first of all have a look at the following demo:
http://www.youtube.com/watch?v=FGn6j3BYg9g#noexternalembedThen you'll need to look for dual-way switching paths on the track. One reasonable initial suggestion is given by the pink arrows on the map below:

There are other (better) ways of pulling it off, though... if you wish further inspiration, the Competition Archives are always a great place to start - pick some of the replays from Z10, Z11, Z12, Z23, Z29, Z34, Z39, Z41, Z61, Z68 or Z79 for dual-way tracks at varying levels of complexity.