B.P.
I'll tell you that I am, by nature, a very schedule-oriented, routine-oriented person! I do have a general eating schedule (with some flexibility, of course!). (FYI, my kids are now 5 and 2.5, if that info helps).
7:45 or 8:00-ish Breakfast (whenever we get up and dressed)
10:00 or 10: 30 Snack
12:00 or 12:30 Lunch
3:00-ish Snack (sometimes this is skipped, sometimes not)
5:30-ish Dinner
The idea here is not to be on a set schedule and punch a clock. There are plenty of times a meal or snack time gets moved or snacks get skipped, but the general guideline and routine is there.
Also, keep snacks as small and healthy as possible. It's just to keep them going until the next meal. And let your son set the pace for how much he eats at a meal. As long as you're offering healthy foods, allow him to eat as much or as little as he needs (so long as there are no medical issues to consider related to his eating, growth, etc.).
As far as what to do if a child refuses a meal, I can't really say. I've never had either one of them refuse a meal! My children are both BIG eaters and, generally, are willing to give new foods a chance. My guess would be let him wait until the next snack to eat. But I'd also be careful about introducing new foods. Maybe a new food along with familiar/liked foods so that he'll still have something to eat, even if he doesn't like the new thing. And introduce a new food several times before you give up. Sometimes kids need to have a food given to them multiple times before they warm up to it.
Hope this helps!
B.