I recently had to replace the OEM radiator with a new after market replacement (I'm here in China and getting an OEM imported would have been much worse than day-light-robbery). Thankfully someone must have needed a new one, so a local company has made a copy of the Suzuki Burgman OEM for a whole lot less money (typical China, which has worked in my favour in this case).
I had to remove all the tupperware to effect the swap out of the old radiator for the new one. But that did allow me to determine that you would or should not really need to remove any of the tupperware just to a pretty decent job of swapping out the fluids.
I'd suggest popping the bike on the centre stand on top of a piece of 4x2 or a couple of bricks or something similar just to increase the height of the Burgy, unless you have a work bench or similar. Undo the rear facing radiator drain bolt, remove the radiator cap, loosen the bottom radiator hose clip then remove the hose enough to allow free flow of fluid. The next step would be optional, since doing so would likely induce air into the "system", and that is to turn the engine over for a short period just to move any remaining fluid out of the remainder of the internal engine water jacket tunnels etc. Once done, reattach and re-tighten the bottom hose clamp and drain bolt etc. Refill with engine coolant using a hose and a funnel (I bought a plastic funnel which has an extra long flexi plastic attachment which works well for just such an application) provided the engine has been left to cool if you ran it to expel any remaining fluid. As you refill engine coolant you would need to lay from side to side, and back again to attempt to remove any air bubbles induced as above.
Once the coolant level is near the neck reattach the radiator cap and tighten. With engine running, check underneath for any leaks. Check operating temp. Both my 650K3 and 650K7 run 3 bars on the temp gauge when at full operating temp.
Don't think I've missed anything out...