Lived in HK for nearly 25 years now and no guesses what my local station is ( <------ ). The South Island line is OK, if a little crowded at peaks, like all HK transport but as it is driverless there are good views out the front or back windows on the 11 minute ride. Some overground, some underground. Admiralty Station is a pain in the proverbial and is getting worse.
The MTR goes up to the Chinese border at two stations, Lo Wu and Lok Ma Chau. You'll need a China visa to go across the border but some people have suggested it is possible to get one at the border but with a UK passport I wouldn't try that myself. There are MTR lines in Shenzhen too which can be accessed fairly easily from both border crossings.
The high speed rail to China is slated to open around Sept 25 but this is subject to a court ruling next week concerning whether Chinese officials can operate in HK without breaching the one country - two systems principles. I find the whole thing laughable beyond belief. If it does open in Sept, best to leave it for a while as it will be a zoo for the first few weeks. There are mainland trains on the line up to the Lo Wu border too, the daily one to either Shanghai or Beijing heads north at around 3:15pm from Hung Hom Station. There are the regular trains to Guangzhou also, some of them double deck KTT throughout the day.
The Macau-Zhuhai-HK bridge should open later in the year too, another white elephant with construction issues, falsified concrete testing records which people have been jailed for, pilings that had to be dug out and redone (on the HK side - not China) due to falsified depth records, reports of protection dolosse blocks around the islands where the bridge goes into a tunnel for a bit, being displaced all makes me think I'll leave these major infrastructure project alone. I'll still take the ferry to Macau or Zhuhai thanks.
the MTR is under a massive media spotlight here due to reports of alleged shoddy construction, variance of build plans and subsidence all over the place in the construction if the Shatin-Central link. This is going to run and run in the media and courts as this is how HK works.
On the brighter side the LRT in Tuen Mun/Tin Shui Wai/Yuen Long is always worth a ride, buses are plentiful and frequent for the most part. Citybus/ NWFB/KMB all now have next bus arrival time apps which are invaluable for planning interchanges, downloadable from your favourite app store.
Lantau island is very busy weekends, as is Cheung Chau, ferries fill up fast. The bus ride along the south Lantau shore is pretty scenic, NLB (New Lantao Bus) should be introducing new E400 on the 3M soon from Tung Chung to Mui Wo. There is also the cable car to the Big Buddha at Ngong Ping if you feel like a change of transport mode.
Make sure you get an Octopus card and keep it topped up. These cost minimum $150 to buy from MTR stations with $100 credit and $50 refundable deposit and can be topped up at the ubiquitous 7-Eleven or Circle-K stores. All buses/MTR ticket machines still take cash, exact change only.
Where I live on HK island, there are scenic bus rides to the south of the island, numbers 6, 6X, 260 from Central to Stanley or if you prefer a more white knuckle ride, the 14 from Sai Wan Ho to Stanley is fun too, especially if there is a jam on Tai Tam dam. (6 goes over the hill whereas 6X/260 go via Aberdeen tunnel and Deep Water Bay).
Anyway, have fun, take a brolly in the summer as it is usually very wet and beware of typhoons as there is one close by now. Late Autumn/Spring is the best time of year.
