You already know my stance on overly ridiculous dynmic elements, but with that being said, I'll offer some feedback on why I think they might be too much, and how I would improve them if I needed to do some this elabrate (You may already know this, but might as well put it down)
1. The Fetch n' Return track piece: My major concern is that it will disrupt the flow of the game, it makes a PL map into a small ctf map, even though it is for a short time, so defenders will get a little confused (do they defend the piece, or do they defend the cart?). They can on the other hand use this as a time to build their defenses up the road, but I don't think (based on my little knowledge of player psychology) players will do that. Also, since the model is not a typical intel, people will be very confused on what to do, so you will need to find a way to show the players, amongst the battle, what they need to do.
2. The Crane: I figured someone was going to do this eventually... The way you have it, again changes how the game is being played out, do defenders defend pick up, or drop off? It doesn't look like the drop-off zone is visible from that pick-up zone, so players again may get very confused on where the payload is and what they need to do -even though it is something simple-. (Perhaps use a sound a que? I think there might be a sound-bite of the annoucer saying "Get to the cart!" that would help... or usage of the hydro arrow signs may work... using both might solve your problem of player confusion)
I do respect and applaud the creativity and ingenuity of what you have done, I just think that it will take a lot of work and a lot of understanding of gameplay for it to work well. You shouldn't ride on the fact people will have played this map over and over, you need to make it so that people can first-time-out pick up on what is needed.