DW, instead of not telling them anything (which is what a guilty person usually does), talks, and talks, and talks, does not confess, and doesn't tell (or maybe know) where the body is.
If he premeditatively cleaned the MH, dumped the body, lied about his travels, why did he admit to the PORN? Why did he take the police with him in the MH, why discuss anything? It just doesn't make sense.
Another point I have is that if the police were in the MH with DW for a 500 mile trip, that would be acceptable as proof of CONTAMINATION of EVIDENCE SITE.