No, there's no need to baste your quilt before you take it to your long arm quilter, but as I understand it, they do like you to have several inches of extra batting and backing all around your quilt top. Like 6" extra maybe? You'd have to talk to the person doing your quilt to be sure what her requirements are.
I can only dream of having a long arm in my future. I'd love it. For now though, I do all my own quilting on my domestic machine (Juki), and I actually find it a lot easier to fit the bulk of the quilt under the needle if I don't restrict the quilt in any way. I just keep it fluffy in my lap and under the throat area. I've tried rolling and restricting it in the past and wound up frustrated. It can seem daunting to have all that bulk in so small an area, but if you just keep fluffing and rearranging, you can get more than you think under there! :) Keep up the good work!
Oh, and I have no idea how long it takes a longarmer to do one that size. Hopefully someone here will have more knowledge of longarming than I do. :)