There was a post that said you could "try to hitch a ride" in the backseat of a training flight. Is this loggable time?? Is that time good for anything.

no and no. You can learn a lot from riding backseat, but it doesn't count for anything.

Also, I spend half of every trip in front of the instrument panel. Is that loggable for anything? Is this time good for anything?

no

A pilot once asked me for my log book, but I don't have one. I sure could build some CHEAP multi turbine time (obviously not as PIC).

no you cannot

The same company providing the planes is the same one that I would get my license through. Also, Does the PIC have to be an instructor for this to count?

yes

Basically, you can't log anything at all unless it's with a certified instructor. In your current position, you may even have the chance to fly the aircraft, but if the pilot is not an instructor, you still can't log it.