1. That commuting set up is a terrible idea. But you're an adult, you're allowed to make terrible decisions.
2. Every program is different but mine (with home call) required fellows to be able to get into the hospital in 30 minutes. On call fellow had to come in for new acute leukemics and bleeding/clotting disasters. Some of us skated through fellowship only having to do this once or twice. A co-fellow of mine recently calculated that he had to come in nearly half of his call nights over 3 years. So yes, you will likely have to stay closer when you're on call.