Yo need a good hiking map of Kõrvemaa, car route atlases are useless. Check the link above to look area map, or visit local tourism information for asking Kõrvemaa maps.
Sport-hiking map is here: http://www.arvutid.ee/tarmo/eol/cgi/kaart/2003034.gif
Aegviidu is the end of the line for the electric train service from Tallinn -- the journey takes about an hour and costs 16 EEK (approx 1 Euro) one-way (you can pay on the train). From Tallinn, the trains leave from platform 8 or 9.