Why I am asking,
I have done the Studio a few times before when all the rides/shows were working and we would leave late afternoon. I felt the Studios was worth 3/4 a day (sometimes leaving before dinner), compared to late hours with the other parks. The lady I am going with does not do roller coaster type and is her first time at Disney. I have done the Tower and Rock n' Roll once and that was enough.
We will be 2 late 60's ladies with no kids.
We will only have base tickets, spending 2 days MK, 2 days, Epcot, 1 day Animal and 1 day ???
Given this is your friend's first time at Disney, I would definitely recommend taking her to the Studios. Sure, you might very well find that you want to leave by the afternoon, but that's fine! You can use the rest of the afternoon/evening to show her Disney Springs and treat her to dinner.
Or, alternatively, have a fancy breakfast somewhere, arrive at the Studios later in the day, and take in dinner and a show (Fantasmic). The Star Wars Fireworks are also excellent, I hear.
IS there enough to do? Absolutely. If you wanted to ride everything, meet all the characters, and see all the shows, you easily could spend two full days in the parks. But, even if you don't want to see all the shows, meet the characters, or ride all the rides, it's still a Disney park. And this is your friend's very first trip, which means she should have a chance to see as much as possible of everything Disney has to offer.
After all, you're already planning 2 days at Magic Kingdom, 2 days at Epcot, and 1 at Animal Kingdom. You're not missing anything so you might as well give her the complete tour!
What is there to do in Hollywood Studios?
Beauty and the Beast, Live on Stage
Disney Junior, Live on Stage
Nighttime projection show and fireworks
Fantasmic
Frozen, Sing-a-long Show
Indiana Jones Show
Meet and Greet with Minnie and Mickey
Muppet Vision 3D
Star Tours
Star Wars clip show in the theatre (basically recapping the movies)
Star Wars Launch Bay (more trailers/behind the scenes, props, and meet-and-greets)
Voyage of the Little Mermaid
One Man's Dream (though apparently it's now called "Walt Disney Presents" and includes another meet-and-greet)
Plus the usual dining and shopping.
Not sure if I've left anything out...?