This is lovely work. There are a lot of nice flowing cuts, and a startling lyrical montage in the middle.
The core problem is that "The Mist" and "Deep Rising" have the same plot structure:
Act 1: Characters go to Bad Place
Act 2: Bad Stuff happens in Bad Place
Act 3: More Bad Stuff happens then people leave Bad Place
However, "In The Mouth Of Madness" has a different plot structure:
Act 1: Characters hit the road
Act 2: Characters travel to Bad Place and settle in
Act 3: Characters explore Bad Place, Bad Stuff happens in Bad Place, people leave Bad Place
In the first two, the different sections of "Bad Place" can be traversed in any order, which gives JW a lot of freedom to create a compelling set of juxtapositions. In "ITMOM", the different places have much stronger geographical continuity, and cuts don't work as well when they break the "characters are here and go there" flow of the original.
All three movies are clipped to maybe 45-50 minutes, and may have entire characters or subplots missing in the edit. I have not seen The Mist or Deep Rising, and they seem perfectly fine as big-budget 45-minute TV movies. I suspect I would be bored by most of the remaining "people do things in Bad Place" action in these flicks. "In The Mouth Of Madness" is the odd one out here, and it shows. I've seen it recently, and it is not improved by the drastic snipping which improved the other two movies. It needed a little tightening, but not this much.
About the use of the Beach Boys: I really liked JW's placements. Frankly, replacing Carpenter's cheesy synths with the Beach Boys would improve most of his lesser work.
Mr. WIllins can really cut!