It's not that hard to avoid turrets fire and do some damage at the same time. Usually you will have some cover from which you can exit both from the left and the right without risking to be obliterated. Exit on the left, pop a couple of shots, wait the M-44 to repair, then get out of cover on the right and pop two or three shots while the turrets turn. They won't see it comin'.
The YMIRs are easy, ram them, shoot some from the mass accelerator, then run for your life while a heavy barrage of machinegaun and rocketry comes at you. I'm playing on Insanity ATM, and this tactic proved to be heavy-risk, but also effective.
Anyway, don't try to retrieve all the data package in succession. Collect two, then go do the first base, then collect two others and go do the second, IE. And remember that two data packs are unprotected, so you have to work only on 4.
Anyway, the Hammerhead is pure BS. It's a damn hovertank, why doesn't it have thick armor and dense kinetic barriers, but just an excuse for a curaiss to protect it? And why the mass accelerator isn't complete overkill? Also, a coaxial or a pair of front-mounted MG(s) wouldn't have hurted at all.