+1 on obonaventure's comments.

Getting your fingers or a wrench under the rear fender is a bit tight but lifting the bike with a jack or getting the rear end up in some way drops the wheel enough to give you more room to get behind the fender. If you don't do this, you can still get in there but it's a a bit tougher.

Doing one side at a time is also the best method. I think that is mentioned in the instructions or I read it in a previous thread.

 

I jacked up the bike and removed the lower shock bolts to give myself all the room I needed. I shudder to think how much of a hassle it would have been if I hadn't taken the two minutes to do this.