It will all be very easy after just one day there. The bus/boat/monorail system is very easy to use. If you want to get back to CBR after your day at Epcot, just exit the park at the front, go to the left towards the bus stops where you will see signage directing you to the right area for your particular resort bus.
If you were to exit Epcot through the back door, International Gateway, you would be able to get a boat to DHS, which makes stops at BW, YC/BC, S/D, along the way.
You could take the baot to DHS and get a bus back to CBR. The boat ride takes about 25 mins, not including any wait times for the boat to arrive. You can also walk...go to BW, cut through the pool area, and onto the walkway to DHS..takes about 20 mins.
when you get to DHS, just walk to the bus stops and get on the bus to CBR.
You will be surprised to find how easy it all is. It sounds intimidating sitting at your computer, but it's really easy once you get there and start using it.