Maximum length for bathroom extractor/exhaust fan vent
In rooms with no shower or bath, 25' should be no problem.  Just run the smooth wall pipe and go with 4" diameter.

For the rooms with showers and baths it should not be a problem if you can get it go vertical into the attic, then slope down towards the exit.  Even at 25' it should not be a problem.  You could even possibly use ABS pipe for the sloped run because moisture will condense in the pipe and create water.  This water, however, should drain and evaporate and not cause a problem.