I found this mission preaty easy,i used just one man for it on the scouting mission,went just to the right up to that large road,& completed all mission's from that area,in stealth mode of course,the less people you use the less chance of alerting them & failing,if you try to use all your men,your most likely to alert someone & fail.
And more importantly only you can set off the alarm & fail the mission,not the computer's men.I did it with the Special Op's guy only.