Hi Greg,
How long did it take to compile the application with VS 2003? Even taking 1 minute for 700 pages seems longer than it should. Do you have custom build actions or other pre/post build steps in the solution that are doing custom things?
To test startup beter, what I'd recomend doing is adding a "hello world" page to the application that simply outputs "hello world", and then set that as the start page for the project. Then try running the project again and seeing how long it takes to load. If it takes roughly the same amount of time to load, then my guess is that the delay is caused by one of the following things:
1) Code within your Global.asax that is computing/caching things that is taking longer
2) Code within an <httpmodule> that is computing/caching things that is taking longer
Can you check to see whether you have any custom httpModules installed wtihin your web.config file? And can you check to see whether you have an Application_Start event within your Global.asax file?
One idea would then be to turn off sessionstate for the "hello world" page (enablesessionstate="false"), and then re-test the scenario. This will let you isolate whether the delay is due to your Session_Start event code.
If you can get this data for us, we can help some more.
Thanks,
Scott