Going to Hong Kong from Guangzhou with the 144 hr visa

Yes, you can. Anyway, here are the steps you will have to follow:

- You will have to book a train ticket even before your departure from Europe. Please, keep in mind that the only eligible train for this option is a through train departing from Guangzhou East to Hong Kong Hung Hom railway station
- You are supposed to book this ticket from an agency and not from MTR that runs the train because MTR does not insert the name of a passenger on their e-confirmation. So, you are advised to use this website for your ticket booking because you will receive an e-confirmation with your name on it.
- You have to make a booking for the train at least 7 days before the train departure
- During the booking process, there is a separate fee that has to be paid because it covers a ticket delivery to the accommodation of your choice in Guangzhou
- To be allowed to book the train, you will have to make a booking for at least for one overnight for an accommodation in Guangzhou where your real paper ticket will be delivered
- Upon booking, you will receive an e-confirmation that you will print out and have that printouts with you as a proof of your transit
- Upon your arrival in Guangzhou, you will also present this ticket and soon, you will get a sticker in your passport and be allowed to exit the airport
- Your ticket will wait for you at your accommodation
- You have to take exactly that train you have bought your ticket for
- This train takes about 2 hours to reach Hong Kong

Basically, just follow the mentioned steps and you will be eligible for 144 hour visa free transit in the entire Guangdong province.

By the way, in this itinerary, Hong Kong is your third country, so Chinese authorities are not interested where will you go after you reach Hong Kong. Also, this is not a visa, but visa free transit. There is no visa at all.