Well, it's been a month or so since I've posted so here's what I've changed/learned about.
It was easier for me to use DateTime than Date, even if I just want to hold a Date field. I also started to really build out some of the more dynamic functionality.
Device types can now be defined on the setting page, tab 1 and I'm using a modal textbox that pops up when you go to add a new item. All that needs is a name so a model makes a lot of sense for that.
When making a new item, the device types are pulled over dynamically and displayed as human-friendly names in a drop down. In the code and going to the back end, it's all using the ID. This field is also nullable in case the device type gets deleted, it won't throw as many exceptions.
I also wrote up the item detail page, though both the new item page and item detail page tell me that I need better UX design / more layout experience. This stuff isn't easy!
Finally on the design side of things, I've added a couple dynamic boxes to the landing page that show how many items and device types are defined. This is another part of the site I'll work to design more as I go.
I'm sure I will find something that looks good and functions the way I want – I just need to get there. And I can tell by where I am now that this project will keep me busy for as long as I want it to.