Glow plugs just add heat to assist with starting. They do a great job, but really should not be needed in most parts of the US in July. If cranking will not build up enough heat, put a hear gun or less effective a hair dryer in the intake as close to the engine as possible. Super heated intake air should assist in heat to start.
Also so long as your battery is still connected, you should be reverse flowing power to the battery and all tractor electrical systems. So glow plugs should be able yo be heated. Of course if the battery on the tractor is dead shorted, this may not work.
Some pictures of how your hood mounts might provide suggestions of how to get it opened or removed without raising the loader.