I have the same kind of problem and some others too. I just post something
about that new IDE not really as good the previous were.

But still one way I found to speed up opening a solution is to make sure
every code window was closed before I close the solution (making sure the IDE
won't start some "strange" procedure before everything is loaded in the IDE)
It helps but doesn't solve the issue. It will probabably save you a couple of
startup crashes also (the bigger the solution the more crash I get when I
leave to many code windows open)

I also found that having connection to DB in the explorer might be causing
some delay when starting the IDE. I'm now using the enterprise manager client
instead on the one built into the IDE... Maybe it's me but I'm starting to
feel like the IDE is simply getting to big!

Hope it makes your life a bit easier (until we get some fixes)