When Ray is sitting on the toilet outside his trailer, he has nothing on except his pants down around his ankles. When he is told to stand up, he can be seen pulling up his pants (and underwear, inside the pants) but as he pulls his pants up, his underwear is already on him, not inside the pants as it would be since he grabbed the pants/underwear at the same time.
Susan Morrow leaves Tony Morrow who is of graduate school age and meets Hutton who is presumably her age in the movie and they have a daughter who is now college aged. Hutton appeared to be much younger than Susan's character like in his early 30's which is true in real life. So he could not have a college age daughter with her.
The phone number on Edward's note accompanying the manuscript has a (323) area code. This is a Los Angeles area code. Supposedly, Edward lives in Dallas and presumably has for quite some time.