Ok, that helps a lot. I would do the following:
1) I'd definitely move that filter to the right a little to give you more room on the other side. Cut out a small section of pipe on the cross piece coming out of the pump and just add a coupler. Also, make a cut before the mineral (blue) unit and after it so you can slide the pipe coming out of the filter to the right.
2) Get rid of the chlorinator. Cut that T out that goes into the heater and add a coupling, another piece of pipe and another coupling on the other side that goes to the filter.
3) You could then make a cut after the T that goes to the booster pump and add a 90 fitting and send the pipe back toward where the chlorinator is. That will give you a long enough run when you turn it back with 2 90's and return the pipe toward the manifold. That's where I'd put the SWG. You'll have to remove that check valve and probably won't be able to reuse it again because there's not enough pipe sticking out of it to reattach. You could go without one, or put in a new one on the piece of pipe heading to the back of the pad before it turns and comes back. Your choice. Most people on here say that you don't need a check valve with a SWG, but I'm not sure I agree. If both the pump and SWG turn off at the same time, chlorinated water can back track back through the system to your heater and corrode it over time. Maybe if the SWG turns off a bit before the pump, that doesn't happen, but for $40, I'd feel safer with one, especially if that heater is in good shape.
The pipe that returns to the manifold, which will have the SWG connected to it, doesn't have to line up exactly where it does now. You will cut out both T's on the manifold and that will give you room to maybe move that return pipe a little further to the right so you don't have 2 90's so close together for water flow.
You could also consider moving that booster pump somewhere a little closer to the booster return line to the pool so you don't have that long diagonal piece the way it is now. Not necessary, but you may find it more to your liking. That's up to you.