This summary is from having been on the Best of England tour. You have been told a lot about what to expect. Now the rest of the story.
First, let me say I enjoyed my BoE tour. Went places I could not have gone on my own. Met some really great people who were my traveling companions. Good folks. Didn't have to plan much of anything, other than how to get to Bath and how to get home once it was all over. Very convenient. I felt the price for what I got was very reasonable. We spent a lot of time on our coach (not bus) but one of the great things RS does is provide enough seats that each person has two seats to use. No scrunching up next to each other. The tour was sort of a "sampler" for me. Covered lots of ground and saw lots of things I didn't even know I wanted to see! When I go back on my own, I will probably re-visit some of these places and stay longer.
But be prepared. You MUST travel light! Decide what you must take, then leave some of that at home. Your hotels will be "quaint" which is not always great. If you get a room with bad beds, ask if you can get another room. You may be able to.
There will be lots of walking. Sometimes in rain and cold wind. There will be stairs in the hotels. Lots of them. Got good knees?
Your tour guide may not learn your name, even by tour end. But do learn everyone's name because they are worth knowing. Learn as many as you can before leaving for England.
Provided meals. Breakfast was always provided at the hotel, although sometimes we had to leave before they opened the kitchen, meaning it was Continental or nothing. The evening meals that were provided were limited in what you could select, 1 of 3 choices, plus a vegetarian option. What you need to know that I did not think of until too late is when you go to the 2 or 3 dinner meals where nothing is to your liking, just bite the bullet, ask for a menu, and order what you want. Sure you are paying twice, but it may be better than the alternative. Do it. Spend more money and get a good meal.
Don't expect everything mentioned in the tour description to actually happen. We were told we would get a bus tour of London. We did not. Our brochure did not say how long we would be at the Tower of London, but the 2016 brochure said we would arrive at Tower of London in the morning, then have the afternoon on our own, meaning we could spend all day there if we wished. Its easily an all-day destination. But our tour got us there at noon, having had no lunch, and we had 2 hours to eat and see the Tower. Really poor planing.
There are various tour guides. Some better than others. Ours was totally inflexible in varying from the plan. Our itinerary called for us to take a walking tour of York on the way from our hotel to dinner. So, rather than postpone the tour and walk us directly to dinner, he marched us around in the wind and a very cold, very drenching rain.
In summary, the trip is worth taking, but pack lightly, be prepared to speak up if your room or bed is bad, don't hesitate to take matters into your own hands if the provided dinner is unacceptable, and you don't have to do everything the tour guide says. If he says lets go walk in the rain, you can say "No thanks, I will stay here".