You may want to re-consider...
...I don't think we're letting English folk into the U.S. these days.
All kidding aside, you'll find B&B's scattered throughout the entire country, but I don't see how that would be MORE affordable than a motel stay. Most chain motels offer some sort of 'continental breakfast' these days anyway.
If you were to camp three nights a week and stay in a reasonable chain motel four nights a week, you're probably looking at about $250-$275 per week.
Good luck and safe driving.
ab