You can define projects and solutions like you can in any other language. There's nothing that will help you with deployment of BrightScript code to your Roku device, although it should be possible to create a shortcut key that runs a script to compress your code with 7-zip and deploy it to the Roku using curl.
For editing, it's easy enough to configure Visual Studio to treat BrightScript files as Visual Basic:
Tools>Options>Text Editor>File Extension - Enter "brs" in the Extension field - Select Microsoft Visual Basic in the Editor drop-down menu - Click Add then click OK
The syntax highlighting works quite well, as do many of the other Visual Studio editing features.
One thing you'll notice is the annoying squiggles that can't be turned off easily for Visual Basic. However, there is a registry hack if you want to disable them:
- Run regedit.exe - Locate the key HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\14.0\Roslyn\Internal\OnOff - Add a new key named Features (Right-click OnOff then New>Key) - Add a new value named Squiggles of type DWORD (Right-click Features then New->DWORD (32-bit Value)) - Set the value of Squiggles to zero (right-click Squiggles in the right pane>Modify>enter 0 then OK) - Restart Visual Studio
Explore some of the other options under Tools>Options>Text Editor (General, All Languages, and Basic)