The solar panel is a bit iffy. I recently attempted to start a tour on the west coast in WA and OR using a very large solar panel that was to charge up a battery pack to power a C-PAP device. The panel was flexible enough to drape over my BOB trailer but because of cloudy, rainy and heavy woods, I was not able to get more than two or three hours run time on my C-PAP. The panel measured 21"x 30". Maybe it would have worked better east of the coastal mountains.
This is not a fair comparison from my point of view. Your CPAP batteries are huge (3x+) in comparison to what the iPhone and GPS combined need. CPAP batteries would be much more difficult to charge from solar, whereas one could charge some AAs and an iPhone. With new iron phosphate batteries being so much cheaper than they used to be, I would just get a 10 or 15 AH battery and plan on AC charging for your CPAP. I have 10AH x 12VDC NiMH batteries, but this is the last season that I am going to use them. Recharging wastes half of the input power as heat. Lithium ion batteries are so much more efficient at charging, and iron phosphate batteries ( 1 of 3 different lithium ion implementation) are a better approximation for the lead acid cells that a CPAP machine was designed to run on.
I do agree with your outcome though. You have to bring AC chargers for cloudy days anyways, and AC charging should be available. In a pinch, alkaline AAs can be bought for the GPS. And rechargable NiMH AAs are going to waste half of the input power as heat. I carry a POWERGEN external battery which should easily give you 3 full charges to your iPhone. So as desirable as solar charging is, I just don't think it is quite ready for prime time yet when it comes to bike touring in the USA.