Interior noises

I bought my 2000 2door ZR2 blazer a year ago with 44000 miles on it. Ever since I've had it it makes all kinds of rattling and creaking noises on any bump. I think it is coming from the interior panels but I'm not to sure also I think it once had an aftermarket radio removed? Any suggestions it very annoying
Also any advise on how to remove the interior panel to see if wires or something is loose.