No reason why you can't do a night ride to the coast on a Friday, just don't call it an FNRttC. Simon is quite rightly emphatic about that. Certainly look at his blog for tips. Having done a few rides of my own- including a night ride last Friday- I'd suggest (at least to start with)
1. Unless you're absolutely certain about your route, do a recce, preferably at least two, day and night. Day makes it much easier to spot potential hazards, places where you need to mark turns, make any necessary adjustments, and so on. But you need to have ridden it at night too, everything can seem very different.
2. Pay careful heed to where and when you're going to stop. 24hr supermarkets and garages are the obvious choice unless you've got a very helpful friend at halfway. Will have a big bearing on your route. Friday nights much easier for this rather than Saturday due to trading laws.
3. Consider where and how your riders are going to return home. You don't want to plan to take trains when there's a replacement bus service in place...