I think you will find you enjoy broilers if you do it right, I do! The plan you have sounds pretty good in terms of housing/pasturing. A few lines of advice-
1) don't take anyone's word about Cornish cross being a bad or dirty bird. If you care for it right you may find them to be one of your favorite breeds of chickens (I have a CX hen I kept from last summer and she is one of my most friendly chickens, lays well too) they free range just fine and I didn't have a single issue besides one scissor beak in my whole batch. Zero losses once they were out of the brooder.
2) depending on your time constraints consider breaking your broilers into 2 or even 3 groups. Brooding 60+ chicks at a time is tough. I struggled with smothering issues when I brooded 70 at once. Even if you separated them by 2 weeks per batch. 60 birds is also a lot to process at once
3) learn to process your own. It saves money, isn't that hard, and also plays into being self sufficient. Yes it may be hard at first but it will make you appreciate the chickens more and you can assure they were treated well right up to the end.
4) growing heritage breeds will take much longer and won't get as big. You probably know that and may not care but still...
5) look for a breed called Dixie Rainbows or similar. I have raised them and they are a great breed. They reached a great size in 14 weeks and they are supposed to breed true. I have 5 hens and a rooster I kept back and hope to breed them this year. My rooster is enormous so I'm counting on his genetics