Take this from a person who does not live in HK..ie me
Look at the 141 site. Find the girls you want/considering. Put their addresses down on a piece of paper. Make a note of the picture showing the girls location if walkup. You can carry this paper around with you. Much easier than trying to log on with your phone while walking around.
Get a map of HK. One of the tourist ones that gives you all the road names, including the small roads. Mark out the locations of the girls on the map. Make note of the MTR exits.
HK is very small. Even if a cab went the wrong way it is not hard to turn back. If you stick with the TST, Jordan, Mong Kok, Prince Edward girls, go by MTR, come out, look at road sign, look at map. Walk. VERY EASY.
The only thing is HK is full of very small roads and can be confusing but after a while, it will all make sense. Do not worry about pulling out your map and looking. You see loads of people doing that all the time in HK. You will just look like a tourist looking for a location. They will never suspect what you are really looking for
I was apprehensive and then just decided to go for it. Was easy to find. Plus going by MTR gives you time to recharge and think if you want to go for a second round