Chatbox to appear in a thread / its own page?
 

To save on server load, how would I have a chatbox exist only on one page of the forum, via a clickable link, rather than consuming resources on the index page, where many users may not be interested in the chat facility.

Hmm, I like that idea... I might explore later on via a DL of a current chatbox etc IF it has re-usable code I'll provide a link. (Later as in not sure when I'll have time so basically think out loud lol).

Add some form of conditional around the chatbox display

<if condition="$forum[forumid] == X">CHATBOX</if>
<if condition="in_array($forum['forumid'], array(1,2,3,6))">CHATBOX</if>

Good Article here

There are also chatbox addons which have full page views.