So it looks as though the iPhone has power limitations (I can overcome to some degree by just shutting it off for most of the trip - we will be at a lodging establishment each niight so can power up if necessary), but I can use it as a GPS via cell service (don't need a data package for that) as long as I use Maplets or MotionX GPS to preload the maps. That would likely work for me since I can get to a WiFi spot if necessary to get train data, etc. Also. Amtrak has WiFi and that is where we will be a lot of the trip. I can do some preplanning and save that information.

If the IPAD had GPS capabilities without a data package that would just about do it., but would still be bigger than I'd like. We are using a 16 and 18 liter backpack for two weeks on the bikes/train/visiting so everything ads up (as you all well know).