The way to get around the lack of RDS connectivity is to run a local ColdFusion server. So long as you have the same datasource with the same name it should work the same when you put it up on the server.
ColdFusion will allow you to install a developer version without a license, at least that is what I have installed. It is for dev only and will be limited to 2 ip addresses that can access it. You can then create and test the pages locally.
Aside from getting the server setup I definitely prefer working with PHP over ColdFusion but this is mostly a personal choice, if you are comfortable with CF then that is the one you should go with.