"Primary" fermentation for a big beer like that could be as long as 3-4 weeks. I certainly wouldn't touch it for 3 weeks myself, except to check the gravity once a week. After that, a secondary is up to you. I would personally secondary that beer for a few weeks before bottling, but I think you can skip that step, assuming your beer is fully fermented out.
That last step (figuring out if fermentation is truly complete) can be a little tricky on big, thick beers like RIS's. One good approach is doing what's called a Fast Fermentation Test when you brew. Basically, pull off a quart or so of your final wort as you are chilling it, and massively over pitch a portion of your yeast into there. Treat this portion as you would a starter, meaning keep it room temp and shake it up a lot during fermentation. You are only trying to see just how far down your yeast will take your wort. Here's the process in more detail: http://braukaiser.com/wiki/index.php?title=Fast_Ferment_Test
Anyway, the whole point of the above explanation is just to say that when your fermentation is done, including a little time for the yeast to clean themselves up (prob around 3-4 weeks) you can bottle. Just make sure you are TOTALLY fermented out. Aging starts the minute your primary is done, and can be done in the secondary, or in the bottle.
And specifically for your RIS, regardless of whether you bottle after the primary, or secondary it for a few weeks, you shouldn't expect the flavor to mature for 2-4 months (give or take). I'd do around 3 weeks primary, around 4-5 weeks secondary, then around 2 months in the bottle before I'd start sampling bottles to see how the beer is turning out.
