Great where ship docks. Direct access into two good shopping malls. Opposite Sentosa Island which is accessable by cable car, monorail or walk; we have visited twice before & love a day there. From port can get taxi anywhere you would want to go or harbour cruise.
As Port Klang is one hours drive from Kuala Lumpur would recommend getting taxi into city & getting dropped at a monorail station then you can get around yourself; pre planning where you want to visit.
Amazing experience; docked overnight so took tour first day which would recommend; saw loads in 5 hours, We are not fans of organised tours but this was great & help appreciated; then felt confident enough to get off alone second day get taxi to "Gateway to India" & take boat trip to Elephanta Island (cheap)& then shop. Lots of people begging & hassling to buy stuff but really no worse than we have encountered in other places.