You could remove all the SiteOffice projects since it is just in the protype stage. You could remove the UnitTest project, you could remove the mojoPortal.Web.Rest project. Everything else is needed for all the features.
I would not change any of the code in any of the projects or you will have trouble upgrading. ALL of your work other than custom skins, should be in your own set of projects which you would add to the solution for custom development. You use post build events to copy needed files up to Web for runtime/debuging, you can see examples of post build events in mojoPortal.Features.UI and in WebStore.UI.
Best,
Joe