As Lifey mentioned, when you plan to take this trip will have a big impact on how much more you could see or do.

I don't think B&B's will be a good choice for this trip. Most B&B's in the US are really more aimed towards romantic getaways, so they aren't always the most budget friendly, and more importantly, I think you'd have a hard time finding B&B's that can will even have room for a group of your size. Staying with budget hotels or perhaps looking at something like Air BnB for rental homes would make more sense.