In this post i show you how you can migrate your existing project to MVC4 and make compitable for vnext.
for visual studio 2010 you can install the MVC4 in your own system through WPI
for migrating the project see the reference
visual studio 2011 not working with MVC3 project without installing MVC3 for it (vnext). for getting MVC3 in Vnext get the setup from here. this can provide support for MVC3 in Vnext
for getting Microsoft web plateform