You can see some of the fireworks, moreso at Epcot than DHS. Although you CAN see them ... that is not the same as enjoying them.
We've been the last few years over the 4th and there really is no comparison between being in the parks and watching from outside.
We've watch the MK ones from Poly & GF after dinner reservations at both and at least they pipe in the music so you get more of a show.
Watched Epcot fireworks from the bridge between BC & BW and while you can see the big ones as they go up, you miss the normal Illuminations and it was difficult to hear the music from inside the park.
And for DHS, you could see a few of them but it wasn't too much of a show. Just some fireworks going off in the distance. They also conflicted a bit with the ones from Epcot.
If you enjoy just watching fireworks at home where they aren't really part of a show you would probably enjoy just fine. But after seeing the ones inside MK & especially Epcot (plus DHS on NYE), I was not to thrilled to be watching from the bridge.
If you have the ability to go into Epcot, you should give it a try ... it really is amazing to see. If not, I think your plan will work out well. They also have a DJ on the lawn at the Boardwalk to liven it up a bit.