I know I'm new to this board, but I have studied dinos all my life and I will give my 2c answers to these questions.
Q: Do dinosaurs have red meat, or are they like birds? Or is it something in between?
A: Not to go against Mr. Goodman, but stegosaurus is described in one of the books as "the new white meat." That said, I would think they would have meat like alligator or snake. But red meat sounds good too. Bronco Burgers, mmmmmmmm!
Q: How far would a dinosaur (a predator) chase someone?
A: As far as they would precive you as a threat, or a worthwhile snack.
Q: Are they really all that tougher than normal animals?
A: I would think so. They are built bigger and usually size and toughness are related. Those huge bones, muscles, organs and hide make for some tough customers.
Q: Could dinosaurs see in color? If not, could some of them?
A: It would depend on if the dinos are brightly colored or not. Seeing in color is only advantagous if color is a matter of life and death. Birds see in color because females are atracted to brightly colored males and since poison dart frogs are colorful to show that they are poisonus and birds don't eat them. If dinos needed to see in color for sexual display or survival, then yes they would see in color. I see it like this: Raptors, Rexs, and other "smart" dinos could see in color, but trikes and most definatly stegs could not.
Q: You might be able to saw off a trike's horns without hurting it too much (for farming - don't want those things poking you), but what about a stegosaur's plates?
A: You wouldn't want to cut off a Trike's horns, since they would now be defenceless against any predator who would want to kill them. I'm sure they make some sort of blunter you can put on and take off for safty. As for a steg's plates, that would be a big no if science is right. A current theroy has it that the plates had blood vessels that would help regulate body temperature, much like an elephant's ears (and both are still warm blooded). They were also probably used as a defence mechanisim, but not armor like most think (all that vital blood in there). Stegs lived at the same time as the giant saurapods, but where a whole lot smaller. Predators wouldn't mess with an Apatosaurus, but a steg would be a great meal. So stegs used their plates to make them look bigger than they really are to try and disuade carnasaurs from attacking them. Some also think they may have been used as a sexual atractor, like a peacocks feathers, but that is unlikely since I have stated that steg's can't see in color (way too dumb).
Q: How often, if you were in the Late Cretaceous, would you run into a dinosaur in the wild at all? Would it be like Africa? Or South America, or North America? Would it depend on the environment, just like it does now?
A: It depends on the type of dino, the area they live in and how often you are there. Think of it like this: We know that the deer population is huge, but you can go into a forest where they live and not see one for days (hunters can atest to that). But when buffalo ruled the western plains, you ran into them every day if you lived there. And as far as predatory dinos go, a lot of prey means a lot of predators, but they rearly want to be seen. Therefore, you would probably run into trikes, stegs, and some form of saurapod every day, raptors and.or rexs every few weeks or so, and some dinos (like stenonychosaurus) you may go your whole life without seeing one. But then again it is also dependent on your GM and his whim for your characters (who might go into territory most people never go to).
I hope I haven't over stepped my bounds with this post, as it is also my first to this board, but as I said I am a great student of dinosaurs (since I was 4, now 22), so I thought it interesting to consider the questions. Hope I was some kind of help.
Dinosaurs ruled the earth for over 100 million years, we only have 99,900,000 years to go to match it. God save the world if we make it!