I've found my most efficient tactic to deal with the LT. It features staying back and drawing the LT out, so I can fight it on neutral ground. This is for when I'm in a heavy or another slow mech.
That is because if you maintain radar discipline, keep your distance from it and keep moving, you're unlikely to get hit. And if you do take a shot, you have a good chance to make it back for repairs anyway.
And actively rushing it is very dangerous, the LT very often kills me just when I'm almost on top of it, it's ridiculous. And if that's not the case, I have to deal with support units that just happen to be there, if the LT is close to the enemy base. Which it likely is.
By drawing it out, I don't have to factor in as many support units and I even have more better attack paths to chose from. It's not perfect, but it's the best I've got.