Here's a link to the park map for Magic Kingdom.
Look for the P by a wheelchair symbol along the red dotted line that marks the parade route. There is one on Main Street in front of the train station, in the hub in front of the castle and Liberty Square area sort of across from the Paddleboat.
Here's a link for the map to Epcot.
The Illuminations viewing spots are around the WS waterway. Look for the Red I with a wheelchair symbol next to it. There are 2 at Showcase Plaza right as you enter WS. There is one between Canada and the UK. The last is the one that phisigprincess mentioned in front of Germany.
For Illuminations, there are many good spots along WS besides the actual wheelchair spots. Before it gets dark, you want to look for the barges sort of in the middle of the water, sort of near where the number 21 is on the map. During the show, a large globe will move between the barges and the show will be centered there. If you have a clear view of the barges, you will have a clear view of the part of the show that is on the ground. Also, be aware of which way the wind is blowing. If it is blowing toward you, the smoke from the fireworks will blow toward you too.
Here's a link to the AK map
The red dotted line shows the parade route and the P with a wheelchair symbol shows the viewing spots. They are all shaded, although you can't tell from the map.
And, finally a link to the Disney Hollywood Studios Map.
There are 2 viewing spots, in front of the Sorceror's Hat. The Block Party viewing spot that phisigprincess mentioned is near Mickey's hand on the map.
All these maps are the regular park maps and you can pick them up at almost any shop or cart in the park.