either the Script (/b switch), or dropping an Acad.lsp in your ..\Debug\ folder should do the trick...
I just drop this snippet into my whatever.csproj.user file (or create it if it doesn't exist), obviously with the folder name edited, and it starts & Netloads AutoCAD whenver I hit F5 on a v2013 project (2013 is what's on my dev laptop). A Visual Studio project template won't automatically create it without resorting to a wizard, unfortunately.
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup Condition=" $(DefineConstants.Contains('2013')) ">
<StartAction>Program</StartAction>
<StartProgram>C:\Program Files\Autodesk\AutoCAD 2013\acad.exe</StartProgram>
<StartArguments>/b "...path to project files .....\NetLoadScripts\AutoNetLoadDebug.scr"</StartArguments>
</PropertyGroup>
</Project>
... or you could just fill it in using the project properties window as per the screengrab attached.
My netload script (from my Project template) only has this in it ...
netload "C:\---Path to Codez---\$projectname$\$projectname$\bin\Debug\ACAD2013\$projectname$Acad2013.dll"
Note you need a new-line at the end of the .scr file.