I have tried this very simple scenario with two novice players. I acted as umpire, though two novice players could try this on their own without one.
The board has outrageously large amounts of terrain on it: more fields and
woods than you could shake a stick at, a village, and a factory complex
(the objective) about a third of the way into the board from the defender's end.
The defender has one company of regulars to be deployed on the table,
plus one on-table mortar, one burned out wreck of a Elephant (but attacker
shouldn't be told that it is burned out, and so may treat it with unwarranted respect), and one dug in anti-tank gun. None of these may be deployed within line-of-sight of the attacker's end of the table, nor even within line-of-sight of a terrain piece from which that end of the table may be seen. In other words, the attacker has at least two layers of terrain to act as cover for his entry.
After four of his initiatives, the defender rolls at the
start of every initiative for his reinforcements, which arrive on a roll
of 6. These are a second company of regulars, perhaps in half-tracks, and another gun (towed).
The attacker has two companies of veterans, with two
mortars for indirect support, and two armoured cars. He can bring these
on all at once, along one table end. The entry-end of the table for the attackers, is entirely out of line-of-sight of the defenders,
and has enough cover for a regiment.
My thinking is this: attacking in Crossfire is difficult for a beginner (I know, I was rubbish at it when I
started). In this scenario, the attacker has at first over twice as many troops as his enemy, and
these can all come on at once safely, and he has four initiatives to use
them at the very least, before the reinforcements turn up. He has two
bullet-proof vehicles to help him, and all his troops are veteran, so
shouldn't mind being pinned much, and should win close combats.
For extra simplicity of rules understanding, you could leave out the vehicles entirely. The novice player who understands the rules, but hasn't developed good tactics yet, may like to have a couple of vehicles to help him along. If you have armoured vehicles, give the defending troops some portable anti-tank weapons, such as panzerfausts.
You may be interested to know that some players get so good at attacking, that they find themselves having to make things easier for the defender.