I have stayed at three different places...
Lost River Valley Campground in one of their very simple camping cottages with 2 rooms- one with a desk and full sized bed and other with a bunk bed. They do have electricity and as it can be cold at night you can request a heater...found out they had them as we were checking out after two freezing nights huddled under layers and layers of blankets.
Franconia Notch Motel- much more "civilized" cottages with your own bathroom, fridge, two bedrooms, cable tv and heat. Owners are very friendly and accommodating. My only complaint was the heater was quite loud and would wake us in the night with awful noises, but hey we were warm!!
Indian Head Resort is my favorite of the three. They have shuttles that pick you up and bring you right to Loon. Rooms are pretty decent, nothing fancy and they have all common amenities. Just a fun atmosphere and some great mountain views!!
Loon is a BLAST, be prepared for crowds though!! BTW each of these I mentioned are very close to Loon. Hope this helps!!
