Rooting Question

Hello, I'm new to the whole tablet thing so hopefully someone can help me with this. I bought a Kindle for work purposes. My intention was to load various reference materials on it to use in the field. Much to my disappointment, Amazon does not have some of the apps I need, but Android Market does. I tried to sideload the apps which installed but I received a message stating the apps were not authorized and obviously the Kindle will not connect to the Marketplace.

So, if I root the Kindle, my understanding is I will be able to connect. I'm not interested in changing the operating system and don't really want affect functionality such as losing Netflix or access to Amazon so can I root and reverse the root? Can the root be turned on and off at will so I can access Amazon and the Marketplace both regularly?

Any help would be great. Thanks.