Thanks again to everyone for all the feedback!
@brendodendo, to answer your questions:
When moving to a paid model, I was planning on simply releasing it as a different app so that the licensing mechanism wouldn't interfere with already-installed versions of the beta. Anyone who downloads the beta versions of the app gets to keep it. I can look into removing the SD card restriction so they can keep it even if they get a different phone.
I hadn't thought about the possibility of making it ad-supported, mostly because I personally dislike the idea of ads taking up space on an already-small screen. I could see what's involved and try it out in the beta version.
I also hadn't thought about a donation-based model, and that approach is a bit more appealing to me than ads. With a lot of donation-supported software, it's easy to "forget" to donate (I'm guilty of it myself), but I think it could work due to the relatively tight-knit and reciprocal nature of the whitewater community.
At the moment, I'm still leaning towards charging for the final version of the app, but I'll seriously consider the other options. I was planning for the price to be in line with that of the iPhone RiverGuide
app- with adjustments based on the feature set at the time of release, so it would be pretty reasonable.
I'm not too familiar with the widget frameworks, but I can look at what's involved to build a RiverFlows widget.
@Boilerblues, thanks for the suggestion- this might be fairly easy to do, especially since AW has a mobile site
that works nicely (but looks like hell on my blackberry).
Some other features I'm considering:
-A search bar plugin so gauge sites show up in autocompleted results.
-Weather reports/forecasts for gauge sites.
-An interface for browsing gauges on a map using your current location as a starting point.
I'm thinking that adding more gauges, performance improvements, and making the app more robust against loss of reception are going to be my development priorities for the short term, but anyone can feel free to let me know if they think other features are more important.