G-T-10

I have a dead mouse, I think somewhere in the AC duct in my 2007 F-150 (it's been sitting in the woods for a few months). Today I removed the cowl panel and noticed the nest right at the cabin air intake. They broke into that useless plastic cover and built the nest. Looks like one of them died somewhere there and now the entire car stinks. I hoped I could find the body in the AC blower, but once removed, it was empty, it did stink though so I think the corpse is somewhere in the AC duct. Any ideas?
I also do not see the way to easily access the nest to clean it. Any suggestions? do I need to take off the entire dash/panel?

Also, do you guys know if other mice would still stay in the nest if one of them is dead nearby and stinks? Just wondering if this nest is still active.