Pa28181 has had exactly the same thought as I did.......
Just go VFR VMC and turn the radio on where necessary. Ditto transponder. Charge the battery prior to start, it's not as if you need electricity to make the engine run once it is going.
If you want GPS use the one on your phone. I once ran the Cub for six months without a working generator, charging the battery every five or six flights. Radio is low load, especially on a listening watch, transponder uses rather more. Don't run the lights.
Have asked around, but can't locate a suitable alternator, you will probably have to do an exchange when you get home. If it is on your way, we can charge your battery at Chauvigny, LFDW. You can get as far as the Deauville CTR non radio from there. You probably won't need a handheld, unless you plan very long sectors in controlled airspace.