Thanks for your detailed reply, this definitely helps!

So the Empire's main attack is striking the base from the North and the escaping rebels are located on the South side of the base. The Shield generator and Command center are both located on the North side. I did notice that when luke falls from the AT-AT after he throws the grenade you can see a AT-ST parallel to him and another AT-AT behind him. Remember too that this is after General Veers gave the order to deploy troops. In the book General Veers is killed by a snow speeder crashing into his AT-AT, before he can destory the shield generator.

Luke is a very lucky guy to escape the ground force and the blockage when leaving the planet.

This is a little off topic

So at the end of Star Wars IV Luke and Han are heroes for blowing up the Death Star.(Also they think that Luke could be a jedi) Why would the Rebels risk sending them out on Tauntuan's in dangerous weather conditions and with unknown risks to place sensors and check for signs of life? Wouldnt it make more sense to have them training rookies on how fly different spacecrafts or maybe assisting with repairing existing crafts. I guess that would make for a boring movie.