Legalities aside, in an emergency and assuming the pilot has the ability to do this, the safest should be a radar vectored ILS into an airfield with no high ground around it. The next option would be a descent over the sea (checking one's position using TWO independent methods, e.g. GPS and VOR/DME beforehand) and I would do that down to 500ft QNH, for a straight in visual approach into a runway close to the coast. The worst has got to be an NDB IAP into some place with hills, especially knowing how bad an ADF will be with bad weather about.