Nice alternative but no need really in campaign mode.
Although it took me 59 tries doing it the wrong way, I realised
you can simply shoot out the alarm & genny b4 tagging ALL
enemy with drone & going straight
in the front crouched with your cloaking on.
Getting out took a little more & resisting the urge to poke your
head out the room to shoot at copters!
While Sams hacking, don't move from crouched stance right
next to where Sam is.
First just sync shoot all the snipers while calling in both rebel support,
diversion, mortar strikes & calling some vehicles will help (simply to assist
in the pyrotechnics of blowing up as many things you are able!)
When there are no copters & you manage to whittle down most the soldiers in
close proximity, simply sneak Sam out the east side door where sniper tower is.
I went on foot till there was a clear space to call in a copter to extract, job done!

The best way to play this in co-op is to have one player skydive in, rest of the squad wait outside and the moment Sam says weapons free, take out the drone jammer and sit tight inside with Sam. I've noticed that if the player inside doesn't fire any shots at anyone or goes prone no Unidad soldiers will detect him so long as the other 3 squad mates are keeping Unidad busy on the outside, this will enable the player in to sit tight with Sam and let him complete the hack. Calling rebel Diversion also leads to Unidad soldiers getting drawn away from Sam's location

Drop and para in they said it will be fun they said. Except every time I try i get spotted by a unidad chopper or dirty sniper or if I finally land they still spot me through fucking walls. R u serious.

i just parachute straight into the building like a lot of other people

I go through the front gate (guard turns his back) set a mine & verge right of shack. When guard goes inside, bring team in. Cross the road, then up the hill behind generator (keep them there). Sneak around & turn off generator. Start crawling behind armory. Use drone to identify all guards. Move to drone jammer then up the hill a bit. Use drone, as soon as guard in doorway turns and goes inside make you move to doorway in and up the stairs (drop prox. mines after inside). [a. If you have trouble leaving generator area ... try flares; b. for more challenge set mines behind the guard in road looking at front gate. Use gate to his left ...craw pass him . Set mines destroy more reinforcements. c. As soon as Sam gives you the word...call a mortar strike on your building it won't kill you ...then take out the 2 dam snipers after you call your team mates (not far away) and all of the rebels. Enjoy going First Class -- through the front gate.

I have a lower en I5 and proceeds to be slow at loading in area details and enemies so i just parachute down directly into the building Sam is in or on top. Then I just enable teammates after the dialogue.

There is another version that can be done as a party. The other players waiting outside, scouting and helping one player inside to start mission, after mission starts the others can join however they wish, guns blazing in. This APC-guide was mainly said for solo players.

This might be the best version, but other easy ways is to do a H.A.L.O. jump on the roof of the building or going through the backside where a watch tower is located near the objective, which I've done always (the downside of that is that the patrols are random so you might sometime have to wait longer than usually because the guards stick to certain locations).

Thank you very much!

Well done. Thnx mate!!!