Well...the red dot is definitely going to be faster than a scope of three or four power. If you are getting shots that are mostly 75 yards, you'd want something fast and that stands out boldly. A 4 M0A dot covers only 3" at 75 yards but is FAST! Even at 150 yards, it would subtend 6" and set easily within a coyote's chest broadside. At 200 yards, you'd be subtending 8" but even that wouldn't be a problem as you'd simply hold the dot on where an equal amount (of the dot) would be over AND under the animal. I've got a buddy who's killed woodchucks at 200 yards with a dot but I forgot how large his was. I think 4 MOA would work great for what you're doing but of course, you can go lower to a 3 MOA or even a 2. I think 2 would cost you some speed though (compared to the 4) because big and bold = speed.
If you are a scope die-hard, then look into a low-end variable but check out the field of view (they're not all the same). The Burris Fullfield 2x-7x has 53 feet of view (compared to the 40's for most 2x-7x's) and of course, the best is the low end 1x-1.5's that give in the 70's and even the 80's. I believe that Weaver even has a 1x-3x doing 103 feet of view but just make sure if you do stay with a scope to get one with a big bold duplex.
Personally, I like that red dot idea myself for what you're doing. Sure make the AR lighter and more streamlined too.