I grew roses for ten years in NJ, zone 6b. I did not take delivery of roses in fall, though.
Keeping the roses in the garage might be safer, especially since you will be tending other plants there; but my bet is that you would be safe putting them into the ground, provided that they don't get hit with a hard frost (for roses that's about 17F) for several weeks. If your weather forecast convinces you that it's not going to get that cold, I'd be inclined to plant them. If they survive, they'll probably have more established root systems in the spring.
