Just getting back in to float flying after not doing it for 15 years,
I agree, never go it alone!!!! Had a friend in the past even try swimming out for a dead plane that he thought was closer than it really was. (against the advise of others). we had to go in after him cause he couldnt make it back under his own steam. NEVER swim for it!!
In answer to your question, Back then, we flew in a cove where the water was smoother and used an RC electric boat of good size, rigged with spring loaded hooks on the back end as a retreaval boat. we would pull the RC boat along side of the airplane hooking it as the boat past and just tow it back to shore.
If the plane was way out there, then we used real boat...The RC boat was much more fun than using the paddles

P.S. I was Kinda Having the same problem not knowing anyone who flies on floats in my area (Las Vegas)or where exactly...
I started a new thread asking if anyone was flying in my area... it took a little while but Got two responces so far. Hoping to get together with these guys soon, Start a new thread, a city that big has got to have others with your same interest....