Hans,
I can't help you with your travel enquires as such, but as for the Hotel, ....why can't your lady book the hotel for you?? She will normally get a much better price than you will probably ever get. I suspect you are right in your assumptions, ....that it's the agency/translation trying to make a few more Euros out of you.....
What i can tell you, The trains in China are pretty good, and if there's a bullet train going from Guangdong to Zhanjiang, that will probably be your best bet as far as cheapness/time is concerned.... if you don't want the expense of a flight. Incidentally, there are always discounts on offer for internal flights and train tickets, (look for between 25/30% discounts) this is another area where your lady could help you in keeping your costs down ......
David.....