Hi Pauline,
Absolutely!
Rather than driving, you could walk or take a boat from Epcot to Disney's Hollywood Studios and back again.
I actually did this very thing myself (in reverse) during my last visit to the Walt Disney World Resort - all because I forgot to purchase a mug from Disney's Hollywood Studios that I really wanted as a souvenir.
Walt Disney World Water Transportation tends to run every 15-20 minutes or so and I would allow up to an hour for the overall journey (including for time which may be spent waiting for the next boat to arrive and the stops that it will make on route) each way, should you decide to travel via this method.
Alternatively, there is a walking path between the 2 Theme Parks if you wanted to walk. Having done this several times in the past, I would say that it would take you approximately 30 minutes in total each way, depending on your walking pace.
Wishing you a magical trip filled with memories which will last a lifetime!
Emma