Living in Port Townsend and often flying to the San Juans, I find that you can limit your over-water exposure pretty easily with a little thought. For example- flying direct to Lopez Island is about 30 miles with 22 of them over the open water. If I fly the Whidbey Island shoreline, it's about 39 miles to Lopez with one 5 mile and one 8 mile "feet-wet" leg. If the ceilings are low, I'm flying the shoreline. If I can get up to 3000' or better, I might fly direct. I have seen people who strike off for that 22 mile feet-wet direct route, down at 1300' or lower to either stay out of the clouds or out of the Navy Whidbey Class C airspace. Foolish IMHO-- if they have a problem, they're screwed. They might still be screwed at 3500', but at least they'd have a couple minutes to hopefully sort out their problem or at least to radio a mayday. According to my airplane's POH, with an 8:1 glide ratio and starting at 3500' I have a theoretical ability to go about 5 miles before splashdown. That's close to 5 minutes, plenty of time for several Hail Mary's & an Our Father or two.
Eric