Congratulations on your new TS. I can't help you out as I haven't even
seen one yet...
You might try driving a regular Transit van, with the high roof and long wheelbase options preferably, to see how it feels compared to your E-450.
The 2390 does look like a nice down size option. The Transit has a very good CCC....twice as much as a MBS. And I like the corner shower, that is one of the reasons we recently upgraded from a MBS to a GTS. I'm just not too sure about that smaller bed...