Im not sure if it's a bad caliper or perhaps a faulty break line..

Two weeks ago we were getting on the interstate and the car started shaking like it was having a seizure almost. We exited the interstate and it stopped. It did it a few more time then would start to slow itself down while driving like the brake was being applied. We smelled a warm rubber type smell and at one point it started smoking. If we shut the car off and pumped the brakes a few times it released and we could continue the drive home. It's been sitting since.

Any way to check to figure out which it is or if it's something else?

 

Sounds like a front caliper is sticking. Either the caliper piston is sticking or the brake hose is degraded and not allowing fluid to flow back. Get the front end off the ground on jack stands, pull the wheels and see if each side spins freely. You may have to work the brakes until it fails. You should be able to tell which side is the problem. If it's both sides then it would be the master cylinder, not likely though. Check pads and rotors for scoring and make sure pad shims are lubed.