Alli,
What seems to work for me...I picked up your standard snorkel & goggles for swimming, some PVC tubing you see for pools(~1.5" to 2" diam), one of those foam poles (~50" long)..they have a hole thru them...large enough for a very snug & epoxied fit onto top of snorkel & end of PVC tube fits in(drilled out) other end(also epoxied). Let that set = results in nice, solid connection. I then get on of those body boards, an inexpensive one...cut hole in it for PVC tubing to stick up thru(tightly..epoxied), then just make the board a little smaller by cutting...and voila, you have a breatheable snorkel & tube(which will float...if you have a big enough board). Try it out to make sure you CAN breathe with it = with goggles & snorkel on you now have a way to take it slow & easy to get the roll correct without having to rush it out of panic....
Works great for me....
Steve