I think I would do an Uber/Lyft or cab rather than walk all the way to DHS to get a bus back to CSR. If you are really against that idea, another option to DHS is to take a bus from the Boardwalk to Disney Springs and transfer there.
But the in general, Even though they say buses run an hour after park closes, I have read the buses won't ever leave anyone stranded. In other words, there is always a bus that will take you where you need to go even if it is beyond the regular hours. An example:
A few years ago we walked from EPCOT to Fantasia Gardens after Illuminations. All the parks closed early that night and EPCOT was the latest park open. After playing a round of mini golf, we walked to the Swan to take a cab back to our resort - The Polynesian. As we arrived at the Swan, there was a bus pulling up with Magic Kingdom on the marquee. It was well after 11PM and The Magic Kingdom had been closed for several hours. I walked up to the bus and asked the driver if he was heading to MK and he asked me "where do you want to go." I said we were heading to the Polynesian so the Transportation and Ticket Center would be great. He said "no problem", drove us to the TTC and we walked from there to the Poly.