Re: Eventually splitting into multiple pages, I'll give my standard warning against subpage proliferation: m:Grants:Learning patterns/Every new page starts off unwatched. Documentation is generally best when as all in one as possible.
Topic on Talk:Team Practices Group/Planning offsites
Thanks for that good advice. I strongly suspect that at some point it will become too large and unwieldy, but you have inspired me to try to keep it all in one place as long as practical. I'll try to err on the side of fewer large pages rather than many small ones.
In any case, I hope this will be the single entry portal, or will be replaced by some other single entry portal. I definitely don't want to have multiple parallel "how to do an offsite" pages!
My current inclination is to split "Where (venue)" into its own page, because it is large, and is theoretically is handled by or WMF admin folks rather than TPG or the event owner. Another possible extraction would be "During the event", to make it easier to access just that material while someone is actually at the event. It's also pretty large.
Extracting "During the event" would make a bit more sense to me, as yeah, it seems useful as a standalone page.
The page as a whole is currently 40kb, which is roughly where it starts to make some potential sense to split. (Though I lean towards mergism, and keeping things centralized until problems actually occur)
I'd encourage leaving "Where (venue)" in this page - for the usual reasons (non-duplication of generics, easier ctrl-F, easier watchlisting, etc).