Strategies for migrating from MVC2 to MVC3/Razor

I have a fairly large MVC2 site and would like to start incorporating MVC3 to take advantage of the Razor view engine. I've seen the Upgrade Tool, but that seems to开发者_高级运维 focus on converting my project (already done), not my pages. The Telerik conversion tool is interesting, but forces a wholesale move to MVC3. I would prefer a staggered move, where new pages are developed in Razor and old pages are converted when necessary / as time permits.

So, what strategies are there to migrate from MVC2 to MVC3? How do you mix the two -- duplicate your Master Pages/Layouts and live with it till you're done converting?