[eitally]

Regarding border crossing ... if you haven't crossed into China before, it's quite possibly worth taking a full-service car that has driving privileges on both sides of the border. For a first timer who might not have much international travel experience, disembarking on the HK side, going through customs & immigration unaccompanied, then finding the right transport on the other side and being able to communicate destination, can be daunting. After you've done it once, no problem, but the first time is anxiety inducing. Also, the lines. If you pick the wrong time and you hit the border with tens of buses in line, you're going to have a bad time.

[culturestate]

Lo Wu and Lok Ma Chau are fairly straightforward; it's really hard to screw up. I'd wager that taking the train to Lo Wu would have been easier for them, actually, because their contact could just meet them in the (relatively) small at-grade Luohu exit that everyone is forced to funnel through.