We're a large family (2 adults, 4 kids, and my mom usually travels with us). Depending on the number of people traveling, we've stayed both on-site and off-site and like both for different reasons. Sometimes my sister and her family travel with us too which adds another 5 people into the mix.
When staying off-site I've never missed being in the Disney "bubble." We stay in Disney themed homes and love having the full kitchen, washer/dryer, private pool, and plenty of room to spread out (last home we rented was a 5 bdr/3 ba). I found driving to the parks took less time than waiting for Disney transportation. I also found that even with renting a car, paying for gas and parking, with what we saved on rooms and food (we weren't locked into eating every meal on-property) we still saved money.
OP I hope you have a great trip and enjoy your off-site stay.