Hello NWCAD,
You have the same major concerns that I have about VB.NET and ACAD. Currently, I have ACAD VS/2002 and VB 6.0. There is no documentation that indicates that VB.NET has one to one correspondence with my version of ACAD. I would suggest using VB 6.0 until Autodesk clears up this fog. You can convert to VB.NET later if Autodesk gives the ok. If you have the time, play with VB.NET and ACAD to see if the application program crashes.
John