For the record, in the browser, once you load a page, you can turn wireless off, but you won't be able to load any other pages.
I'm not sure what an HTML
tree is, but have you tried letting Amazon convert it?
Send it to your kindle email address (usually
something@kindle.com, but add a free:
something@free.kindle.com if you do not want to be charged for the service)
You should be able to find the email address here if you do not know it:
https://www.amazon.com/gp/digital/fiona/manage
After it is sent, Amazon will send you an email telling you that it has been converted. Then, from the link in the email, you can download the converted file and load it onto your Kindle over USB. (If you send it to
something@kindle.com, it can deliver the document over 3G, and if you send it to
something@free.kindle.com, it can send it over WiFi to your Kindle)