I know, I know people here do not do tours
 

My sister wants to do a guided tour of Spain. Although we know Spain well, we do not know tour companies. And yes, Fodor's is for independent travelers, but is anyone familiar with middle of the road cost, rigors, and interests tour group. She used Gate 1 for Italy and liked it. That would seem like a logical choice for Spain as well. She likes the greatest hits tours. From what I hear Little Ricky does too much walking. She is early 70's likes to shop, is not art devotee and is not an adventurous eater.

Thank you.

I'm not a tour person either, but your sister might want to look into OAT - Overseas Adventure Travel.
I've heard very good things from friends who've traveled with them to some of their more exotic destinations than Spain: Africa, Far East and South America.
They do not charge a single supplement, which is very nice.

Touring Spain with a group
 

Your sister should stick with smaller groups that specialize in Spain, not the world, and I'm afraid that includes Rick Steves. Of course it's difficult finding the right one because there really aren't many companies organizing regular small group tours to Spain or anywhere else in the world. And is she were to find a good one, not everything will fit. Petrabax does offer some interesting group tours, but she'll have to check them out (https://petrabax.com/#!/tours/en/escorted,2017).

She should start her research with some of the groups that travel through various programs at universities or in her local community. I know that both Harvard (https://alumni.harvard.edu/travel/trips) and Princeton have some travel groups and normally will accept those not actually associated with the school. And then of course, she can always use a good travel planner and not have to end up going with a group. Check "travel planning services to Spain" on Google.

Hope this helps.