Hi, Debbie ...
I've never been to KL on a cruise ship, but have been to Saigon.
I don't know the port you mention for Saigon, we docked right "downtown" but it was a very small ship (Song of Flower).
We did take off on our own in the city, no problem ... but I wouldn't attempt going any further.
Check my website http://happysails.com
for a Viet Nam story.
pamda -- CM First-Time Cruisers Editor