Hi Nicole,
It's difficult to predict how long a bus ride will take, but I'll give it a shot. I'm sure you know the bus stops at Disney's Hollywood Studios get very crowded after Fantasmic! Depending on how crowded the park has been, the wait can be a little longer for the right bus to come along. If you are going to the TTC and then
Disney's Contemporary Resort by Monorail, I would expect it to take at least an hour and a half, perhaps (probably?) longer.
If you aren't attached to riding the Monorail, you could always take the bus directly to Disney's Contemporary Resort from Disney's Hollywood Studios. I think that would take at least thirty minutes off the trip! If you were hoping for a Monorail ride, you could always take a ride on the Resort Loop after your dinner, depending on whether or not the Monorail is still running. We love to go on a Monorail shopping trip. We stop at each resort on the loop and make a small purchase.
Thanks for stopping by the Disney Parks Moms Panel with your question!
Wishing you a magical vacation,
Amy H