if your coming up the m6, the easiest most straight forward way is up the m6 to junction 19, come over the onto the a556, then straight onto the m56 straight onto the m60 and cut around stockport on there and get off at junction 23 (ashton under lyne) then follow the a635 and its about 10-15 miles it will take you staright over to meltham itself and theres some good roads out that way too, if you come over greenfield (you'll see dovestone reservior athe bottom of the hill) there are 50 mph speed camera signs but there are not any cameras up there at all.
Plus theres parking up meltham mills road (the industrial estate is shut at weekends) so if you cant get into fred lawtons you can park up there on the road side, i wouldnt go up near the tip though they have trucks coming and going all day and dont care much if your in the way.