Hi David, long time no see!
I haven't played those scenarios before, but I have a few suggestions that I'd like to throw in for the heck of it:
1. With Huib's scenarios (which are some of the best and a joy to play), you must study the map very closely. Often, there is a secret or "trick" to the map that will let you in the back way. Once, an opponent of mine lost a scenario when he failed to notice a shallow in a major river. I blew up two bridges, and he resigned, never noticing the 'back door' in the map.
2. Remember the 'harmony' of infantry advancement under fire:
a. the turn before the advance, figure where you could get your infantry in the next two turns.
b. lay down smoke at the end of the current turn (if you have the artillery for it)
c. the following turn, move the infantry into the smoke (should be 3 or 4 hexes toward the enemy if possible), and bring loaded carriers closer to the front line.
d. take your losses for the turn (it happens to everyone), but take solace that the smoke lessened your casualties.
e. the following turn, 'burst' toward the enemy - now that the smoke is gone, double time your infantry and move them as far as they can go. Even through forest, they will often move two hexes when double timed. A lot of people don't know this!
f. Move your carriers up to where they can unload AND move back a hex. Otherwise, the hex will likely by overstacked and you'll take extra casualties from fire and artillery next turn.
g. if you have the smoke for it, wash rinse and repeat. Often, the extra visibility gained from this advance (which should carry you 4 hexes or so this turn alone) will make repeating this method unnecessary, unless you run into a new line of resistance later.
This method should move your infantry 4 to 8 hexes distant in two turns, depending on terrain.
When it comes to mines, if my situation is desperate, I look for the strength of the mine in view 4. It will have a number on the counter that will tell you the mine strength. If you're facing losing the scenario if you can't get through, move your infantry (one at a time) through a strength ONE mine - as many as you need to. Desperate times call for desperate action!
You can do this with vehicles too. Yes, you'll take a few casualties and disruptions, but sometimes it may be your best chance. Best results are with low-value infantry.
Anyway, that's one method I use when up against really tough odds - almost always better to let the infantry take the hits in a scenario and preserve your vehicles.