Hi John,
There really isn't a substitute on the iPhone for getting the pictures off rather than getting the phone to boot up and connect to WiFi or dock connector to offload the photos.
Rice doesn't dry phones any better than a few days in the sun would dry a trashbag of wet clothes.
It is entirely possible that with prompt cleaning and a new battery, the iPhone could live again. I just got done doing the same repair for a customer whose iPhone met a caramel latte before she was able to back up her photos from a once in a lifetime trip.
The thing *not* to do is try to power on the phone before its been cleaned. In my customers case, she tried doing this after rice repeatedly, and the end result is that the heat generated from an internal short caused serious damage to the baseband and her phone is now a really nice iTouch.
Start by following a guide to open the phone, remove the logic board, and clean the whole thing with 99% isopropyl alcohol and a toothbrush focusing on any corrosion you might see. Unfortunately, most of the iPhone 5 logic board is difficult to access under soldered on shields. A thorough cleaning requires removal of the shields--which can be difficult without bending the board or knocking off components. You may wish to invest in an ultrasonic cleaning machine that may help if you can't get the shields off. Let it dry on its own and reassemble with a fresh battery and see what you get.
Feel free to contact me if you have other questions---I just finished doing a repair just like this tonight!
jessa