When ever i build with Umbraco i find that i have to manually include files / folders into Visual Studio to be able to edit them with intellisense.
The is especially helpful when working with Views, to add the Views folder and all items under it recursively to Visual Studio just follow my tips below:
Unload your project by right clicking on your project name and clicking on Unload Project
Next right click your project name and click Edit PROJECTNAME.csproj
Once you have opened this file remove any lines containing the following:
then when you have done that include the following line:
<Content Include="Views\**" />
Then just simply save the file, right click on your project name and then Reload Project.
All of your files under Views should now be included in your project and usable with intellisense.