It can be done, but yeah, you'll be tired.
We went from DC to SWF on July 4th two years ago.
But we stayed at the Renaissance Resort, which is literally across the street. We came back from DC at 5pm, rested, got some free snacks in the club room, then went over to SWF and saw the fireworks. Place was packed, we went straight to the ski stadium and got a seat near the front of the orchestra. The last Shamu show finished, those people came over to the stadium overflowing into the grass. The fireworks went off, great show, and then everyone headed for the exits. It took about 30 minutes to get out of the park because of all the people, but we had fun.
If I was doing it today, I'd probably go back to the hotel, get cleaned up, go back to SWF and eat at the waterfront area, catch the last Shamu show, the fireworks, then leave.