Long distance miles are best mainly for 2 reasons 1) engine is not start/drive/stop - short trips kill engines because like your favourite oil commercial says "most engine wear occurs at start up". 2) Engine is running at easy, open throttle and no fueling up happens (probably not important with modern factory or well calibrated fuel injection).
My car sees 4000 + every day for about 30 mins, tear down looked like a Mobil 1 commercial minus 1 x Peter Brock.
P.S if your tacho reads 3xxx, it is probably stuffed and should be replaced immediately with an Autometer moster tach. (JK)