Personally, I think we are supposed to rank possible rout destinations based upon direct MFs required for the brokie to reach them - regardless of enemy presence. It's much simpler although situations can still get very complex (the other way leads to much madness!). Frankly, I think it's crazy that such a basic concept can
still be so poorly explained by the RB.
For the OP example: K4, M6, and N5 are all 3MF away. Afterwards, we ask if the unit can legally rout to each Location.
Since it can't rout in any of the above 3 cases, we proceed to those Locations that are 4MF away and repeat the question of legality. Here we find four options - K2, K6, O6 and P5 - but only K2 or P5 can be chosen as the others require moving closer to a KEU (K8).
Once we study K2, however, we discover that the unit could almost reach it legally (N3-N2-M2-L1-K2) except that the last step would move it closer to K8 after having moved away.
As for P5, this one could have been ignored since it is no further from K8 than when we started. But regardless, the only path there also moves the unit further then back closer to K8 (from P4 into P5). Thus, we move onto Locations that are 5 MFs away...
I think this leads to the following answer: P1 must be the target. In any case, Low Crawl or interdiction (assuming it didn't surrender anyway)!
NOTE: I obviously do not believe that the RB text beginning "Assuming it can abide by the previous requirements..." is at all referring to the calculation of
rout MF. It is simply saying that the literally
nearest Location(s) must be chosen if the unit can legally get there:
Assuming it can abide by the previous requirements, a routing unit must move to the nearest (in MF calculated at the start of its RtPh)
Otherwise, I think that the parenthesized text would need to be
much clearer:
(in MF calculated along a legal rout path with regard to KEU presence at the start of its RtPh)