River lines, minefields and dragons-teeth oh my!

Operational rules for crossing major barriers.

I am developing my WW2 North Africa armies for operational games and one of the items I want to address are minefields.  These are hugely important in the desert campaigns and were used extensively by both sides.  I ran my ideas past Mark over the weekend and we actually came up with a generic rule for all major barriers which would have influenced all our previous games significantly.

In the desert most minefields are anti-tank which do not impede infantry movement.  However, it was very difficult for infantry to move far beyond the minefields without clearing a path for their support weapons and supplies; how best do I represent this?

Any infantry that cannot trace a clear line of supply will shoot on a -1 (but does not effect close combat). Simple!

Now, let's take it another step further.  Any troops that cannot trace a line of supply over a major barrier; river, minefield, dragons teeth, antitank ditch etc will also shoot on a -1.  Thus in our last game the paras would have been shooting on a -1 until I had built bridges (which I would have needed to ensure were not under direct fire) to relieve them.  If their anti-tank was a 6 against tigers this would have been further reduced to an 11 or 12 to kill.  This makes bold use of paras more dangerous but it would also have been the same for infantry crossing by buffalo!

Then let's take it even further.  Any troops which cannot trace a line of supply to their reserve/base table are also shooting on a -1.  This encourages wide sweeping counter attacks, which I expect to see in the desert, but would have effected our second operational game when Jon would have been rewarded with his wide outflanking move against Phil's rear which would also have supported Russ' counter attack with the AA battalion!

I did consider making any unit cut off revert to hold orders but this would prevent break outs.

Coupled with the decision to limit aircraft to a ratio of 5;3 I think this would address the issues from the last game.  Let me know what everyone thinks.