4 rides?! That's IT? Pfft. I wouldn't even waste my time.
To it's credit, MGM only has one more.
As for a day of attractions I think USO is probably the better park for repeat visits. However USH has the three hour I believe tour which is the hilight of the day.
You're thinking of Gilligan's Island. USH's studio tour is "officially" 45 minutes (and will soon be shrinking due to their weird development plan.)
And just for comparison's sake, here's the full list of USF attractions:
Revenge of the Mummy
Men in Black: Alien Attack
Terminator 2: 3-D
JAWS
Shrek 4-D
E.T. Adventure
Back to the Future
Earthquake
Fear Factor Live
Jimmy Neutron's Nicktoon Blast
Beetlejuice's Graveyard Revue
Twister -- Ride it Out
Universal's Horror Make-up Show
Woody Woodpecker's Nuthouse Coaster
Animal Actors
Curious George Goes to Town
A Day in the Park with Barney
Fievel's Playland
Lucy -- A Tribute
The Blues Brothers
and IOA:
The Amazing Adventures of Spider-Man
The Incredible Hulk Coaster
Jurassic Park River Adventure
Dueling Dragons*
Poseidon's Fury: Escape from the Lost City
Dudley Do-Right's Ripsaw Falls
Popeye & Bluto's Bilge Rat Barges
The Cat in the Hat
Doctor Doom's Fear Fall
High in the Sky Seuss Trolley Train Ride*
The Flying Unicorn
Pteronadon Flyers
The 8th Voyage of Sinbad
The Caro-Seuss-el
Camp Jurassic
Storm Force Accelatron
If I Ran the Zoo
One Fish Two Fish Red Fish Blue Fish
Jurassic Park Discovery Center
Me Ship the Olive
* These attractions have two different tracks, resulting in two different ride experiences.
(Yes, this was all off the top of my head. If I'm missing anything, feel free to chime in.)