If you go right the way through you cross through 3 locks and a lake. If you do the partial transit, you go through the Gatun lock and then turn around at the Gatun Lake. One lock or 3 is the question you ask yourself?
A full transit usually starts at about 8.00 am and ends up exiting the 3rd set of locks at around 4.00 pm after which you sail under the bridge carrying the pan american highway and out into the Pacific ocean. I've been through 3 times and I always view the Gatun lock as a taste of things to come but it depends what turns you on. It's a bit of a giant boys toy and I have found that some women find it a bit boring after the first lock (sorry if I sound sexist).
Hi Bradley - you are right - yes it must be a 'boy' thing because IMHO one lock looks very much like the next.