Say a counter balance is to have 90 degrees snap onto the pallet. If there is some other obstacles or it is so close to the pallet so that there isn't enough clearance to turn. What should I do? My thought is to make backwards drive until it fits, but it takes up a lot of CPU cycles to do so. Like Local Repair, method....testing for so many paths until it finds one

I have no idea what you are talking about. Context? How about a picture or a diagram?

Say the red box is the pallet, the blue one is the counter balance

The black boxes are obstacles, the forks of the counter balance has to enter the pallet at a right angle.

Here I can't do so because they are too close.

by counter balance you mean forklift? you can put one of the forks from the forklift in to the pallet at an angle and drive forward while turning to turn the pallet - then you can pick the pallet up.

Is this a programming question?

I'd like to know how to program this AI, should I precompute a path that can/cannot satisfy the constraints, then re-compute again.

would be a waste of efforts