Sounds like a great project!
Depending on what kinds of "contextual material" you have in mind, it
might also be helpful to use the ExhibitBuilder plugin to present that
context. The pages for individual items are great for presenting the
items themselves, but presenting context is often better done with an
exhibit. That said, the displays Neatline produces do offer some nice
tools for context about the item without forcing it into the description
field, so that might work well, too. I'm not sure if Neatline's displays
will play well with TEI Display and Doc Viewer, though.
Alternatively, you might find the Item Relations plugin helpful for
building links between related items.
I haven't directly used the TEI Display plugin myself, but I have made
use of the XSL stylesheet that it uses. I've been pleased with the HTML
they generated (indeed, I used it because I was not happy with the
product of the XSLT from TEI itself for my project). But anytime we
start talking about transforming TEI, it's possible that you'll
encounter quirks between the encoding and what the stylesheet expects. I
find that inherent to the nature of TEI encoding. And so, I'd say watch
for the possibility of quirks in the display, and the possibility of
tweaking the stylesheet. Keeping in mind that TEI to HTML always loses
information, it might help to start thinking about what features of your
transcription, if any, need to be maintained in the HTML.
In my experience, _any_ project can easily turn into having bit off more
than you can chew! Maybe that's just me, but I'd say that it's okay and
expected to make decisions about what you are _not_ going to do with the
project, just to keep it masticable.
HTH,
Patrick