I've been there as part of an organised trip, so I am not really the one to ask how a 'normal' visit would be. Things were organised for us (as an exchange) which might be very different from a casual visit. Its not something you can do on an afternoon from HK. The travel is quite long, and you would probably have to leave out the Foshan ancestral temple with the temple for Wong Fei Hung which is a must-do when you find yourself there. I advice to stay at least a night, maybe two. Then there's also Chinwoo which you might want to visit ...
Check out when they do liondance/kungfu demonstrations. Although modern, its absolutely brilliant. They do have some displays and all (although in Chinese) and some things like stonelocks its not a full fledged museum of any sort and worth to visit for that reason alone.
Personally, I liked the Ancestral Temple more. That complex of temples is brilliant. Take plenty of time there. If you're into that kind of stuff even a day wont be enough.
About travel between the two (or three) locations you will have to ask someone else, I hope someone steps in. We got traveled around and to be honest the distance between the three locations might be quite undoable in a day or 2, or it might be very doable, we had a very busy schedule so its a bit hard for me to judge
