service at barn, sub at house?

I have an unusual situation. I'm preparing to connect power to the premises for the first time. The Main disconnect and point of entry will be at the pole barn 40 ft from the power lines. The house, 200ft away from the barn and 240 ft from the pole, will be fed from the panel installed in the barn via 4 conductor 4ought Al already in place. Question is, do I need to install a full 30 breaker service panel at the barn where I don't need all those circuits?
And does the house panel then treated as a "subpanel" and wired accordingly?
Thanks for the help,
Dick