From: Houston, TX
I am a bit confused about the "Commonwealth Boundary Penalty" w/re/to Axis reinforcements ....
Seems to me, that if that boundary abides, then Axis reinforcements will be "penned up" behind the boundary?
No. It penalizes the CW for crossing it prematurely - no penalty for the Axis. (I don't think you need to worry about it, though - you'll be doing good to get to Benghazi before Rommel is on you.)
If (as Commonwealth) I decide NOT to take Tobruk / Derna,
then will that keep his reinforcements penned up?
No. If you take both fast enough, the penalty will be canceled - this forces the Italian player to make some effort to hold you up a bit instead of just running for the map edge. Again, this won't be an issue for you.
Perhaps then (OTOH) there will not be enough VP hexes for me (as CW) to score a victory?
There is only a smattering of VPs in the map edge area, and the prohibition only lasts for a few early turns prior to Rommel.
Seems like I need to take Tobruk / Derna ... but not too quickly.
No. Take them as fast as possible. But, as I said, you're not going to need to worry about that.