If you can get the boots off, the spark plugs shouldn't give you too much trouble. Some have removed the rear engine hoist bracket (the black metal bracket that holds the sight shield in the back) to give a bit more room to work. Slide your arm under the heater hoses, and above the power steering pump (watch for the clamps on the hoses....they'll tear up your forearm) to get to #2 & #4 from the passenger side. Use your left hand, and pass the wrench down with your right once your arm is in there. #6 is generally easier from the driver'* side. The front plugs are a breeze in comparison.
Edit - By the way, welcome to the forum, and could you add the year and trim level of your vehicle in your profile? It will helps us to be able to give you accurate information.
Black 2000 SSEi, Silverstar Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, drilled 180 degree thermostat, Intense FWI, PCM, shift kit, and 3.4 Pulley. Solid front mount.