0) Don't live in the past. Switch to MVC4, and if you can't upgrade a full blown version of VS to 2012, just download a
Web Developer Express edition[
^], I am pretty sure, it will be enough for you for the start.
1) Use
entity framework[
^] as "DAL+BL".
2) If you need to manage multiple and large files, you better use the
FILESTREAM[
^] functionality of SQL server instead of BLOBs (
varbinary(max)
), here is an example how to integrate with EF:
http://blogs.microsoft.co.il/blogs/bursteg/archive/2008/05/12/ado-net-entity-framework-support-filestream.aspx[
^]
3) Windows authentication is quite straightforward in
MVC[
^], mostly managed by
IIS[
^] itself, but authorization might be more complicated, especially in a domain environment.
4) Jquery is a good approach to the navigation, but better step forward with your environment than step back with jquery.
5) "webparts" are not mvc concepts. You can control anything, you have full control over the emitted html code, more than with web forms. But the possibility of editing the document is really dependent on the document format. So there is no single answer to this.
6) You might look around here to see some CMS implemented with MVC:
http://www.codeplex.com/site/search?query=mvc%20cms&ac=4[
^]