OK, I've tried this mission about twenty times. I've tried making every single pilot in the mission a Top Ace.
Still get blasted out of the sky every time.

I have no problem taking out the shield towers. Problem is, enemy fighters just keep spawning, and I try to stop them from killing all the Y-Wings before they get into torpedo range and get killed for my trouble.

I could manage if it was just TIE Fighters and Interceptors, but the goddamn bombers keep destroying me with missiles (I'm pretty sue I was able to blow missiles up when I was a kid. I almost never manage know).

Any advice? I think I've tried everything short of buying a decent mouse/joystick.

Have you tried reading the strategy guide?

Yes. That was pretty much the first thing I tried.

I blew up the star destroyer with lasers from the bottom of the hull while occasionally taking out a tie or two. Most of my wingmen didn't make it around after when the towers were destroyed, so, per the norm, it was pretty much just me...sigh.

The ones that did survive basically served as *my* distractions, not the other way around :)

dont know if the mission in xwing dos is harder than in 95, but i just did it on the second try:

ignore all the enemy fighters, ignore your wingmen, maximize your lasers recharge, make a run for the shield generators and finish the star destroyer off with lasers by hit and run tactics. make sure your shield's fully charged at all times and watch your missile lock-on light.

using corkscrew is advised while flying away from the destroyer to avoid getting hit by enemy fire.

Anybody know how long it takes for the Y-wings to blow the Intrepid after the shields are down?

I can get the shield generators blown up without a problem, but I'm too busy taking on ALL the enemy fighters to get in a strafing run on the Intrepid itself...

Played the mission again and didn't have a bit of a problem. Seems like it all depends on you getting the shield generators down before a wave of Y-wings make their approach. If the shield generators aren't down, the spend too long pursuing enemy TIEs and getting blown up before the next wave of Y-wings comes along.

My playthrough (remained the same since 1995 hehe...)
Direct all cannon and shield power to the engines, maneuver so the two towers are aligned. Take them out with three torpedoes each. Try to do that in a single run.
Continue flying straight while cork screwing. Move out from the STD's turbo laser range (~2 klicks). Destroy the pursuing fighters. Use full cannon recharge rate and zero shields recharge rate to take out the TIE Fighters. This will even your speed with theirs and will also make it hard on the TIE Bombers to achieve a solid lock on you. Use full cannon recharge rate and normal shield recharge rates to dogfight the TIE bombers and use linked cannon fire.
When you see your RWR lights up (the flashing indicator of a locking missile), turn back to break the attacker's lock. If a missile was fired at you, increase your recharge rates to maximum and and loop when the missile is at the sides of your front/read radar. Don't try to shoot missiles unless they are fired from 1+ klick range.

If I recall correctly, there are three waves of Y-Wings, three ships each. Engage their attackers using the above tactics and you should be done without even helping them.