When Greg is checking the burn victims clothing for signs of accelerants, he is using a hydrocarbon detector. It shows the presence of hydrocarbons in the clothing with a strong return. Later he tells Grissom that it tested positive for the presence of alcohol. Alcohol is not a hydrocarbon fuel but is in fact a polar fuel (one that binds with water).
When the amateur astronomer sets up his telescope, we see a brief shot of a man undressing in a window, then the telescope is elevated to show that the target is really the constellation Orion. Both are shown right side up. An astronomical telescope inverts images, so both should have been upside down.
The guy with the telescope would've felt the heat from a fire that big, before even smelling the smoke from it, so he should've known where it was coming from without any difficulty.
Though the area is supposed to be dry and brown (thus the fire danger), the sequence in the hills was filmed in the late winter in California, so the backdrop is lush and green (and not a fire hazard), quite different than the "brown and dry" conditions spoken of in the dialogue.
When Grissom explains to Sara the etymology of the word 'vodka' he claims that it derives from the Russian 'water of life'. The words that he says in Russian - 'pshenichnaya voda' (with a very bad accent, too) simply mean 'water made from grain'. In fact, vodka originated in Poland, where it was called "gorzalka", meaning "burning water". In Russian, "vodka" is a diminutive form of the Slavic word voda (water), which translates literally as "little water".