Hi I can answer some of your questions:
1) I personally find it very easy to type on the Kindle Keyboard and find it much easier than trying to type on my iphone. I think for writing out a couple of paragraphs it is absolutely fine for most people. I can write extensively so I probably could write a book on it! It isn't as easy as typing on a laptop but much easier than smartphones I think.
2) Gmail is no problem at all providing you know how to access it, see my blog post if you need more info:
http://www.kinworm.com/2010/10/gmail...-kindle-3.html
I don't actually use any of the other sites you mention so I couldn't say. I use
www.simpletext.ws because I find it a very handy online notepad being that the Kindle does not yet come equipped with a separate notepad.
Re Google Maps on a Kindle - you might want to read this blog post (not mine but a great site) :
http://kindleworld.blogspot.com/2010...r-from-to.html
Hope that helps somewhat.