The condensed version of what I'm trying: I decided on one breed for the roo, Dark Cornish. I have hens of various breeds and cross breeds, and I'll be getting some more pure bred hens of various breeds at some point. The standard Cornish has been used with pretty good results as the terminal sire in meat crosses before, that's why I went with Cornish.
This way I don't have 2 flocks, I let all of them run around together. When I want to hatch eggs from certain hens, I can isolate those hens and collect the eggs until I get enough. I can single a hen, take her off the roost at night, and put her in the isolation pen, until she lays her egg the next day, then go ahead and let her out to free-range with the rest. That way they don't get all stir crazy being penned up, and i still get to choose who's eggs I'm hatching.
My target hen breeds are Brahma, Buckeye, Orpington, Dorking, and crosses of these, (that's mostly what I already have, the crosses are mostly with either Brahma or Cornish, plus some odd birds here and there, EE's and what-have-you) and I want to add more Dorkings, some more dark Cornish hens, Salmon Faverolles, and maybe some Marans. I'm open to other hens as well, really anything that's a decent meat bird, that I can find good quality ones from a breeder. I don't want any hatchery birds if I can help it.
My goal is a bird that will be big enough (3.5 lbs? 5 lbs? Bigger's nice, but even a 3 lb. bird would be fine) in less than 18 weeks. I've let plenty go 20-25 weeks, and they're big, and really tasty, but younger gives more cooking options in order to have tender meat. I love my crock pot chickens, but I also like fried, baked, and roasted. These hens are mostly good layers, too. Not record breakers, but certainly enough eggs for us. Right now I have way too many eggs, more than I can use and sell.
The rangers, and also red broilers, sound like they'd work out pretty well, too. They can breed naturally. They won't breed true, so the offspring won't all be big and meaty like the parents, but enough of them would be, you'd have a fair number of nice fat ones, and some smaller ones, that you could either let stick around to gain some more weight, or butcher them small and have some mini-chickens for dinner.
As I've mentioned before, I think the mostly overlooked concept of enough deserves revisiting. These days we tend to want bigger/faster/stronger/more/more/more of everything. We don't need most of it, and would be perfectly happy with enough, if we let ourselves.