There should be a rubber boot on the end of springs. This can be a bitch, Put a bit of grease between spring and boot. That will hold it in place. Question, Does your Patrol have lift kit? Does the rear sway bay have extensions? If you are just doing the rear this weekend it is really quite simple. Front is a bit more tricky. Not taking anything away from the advise above, But for the rear you should only have to jack the car up and the spring should loosen up. worst case, put bottle jack under axel of opposite side you are working on, That will take the pressure of enough to remove or replace. If you have basic mechanical skills 2 hours max for the rear. Unless bolts are seized. Hope this helps.
Steve