HoT HP Train: When are they & what do I need to do to prepare?

I just got my old main (Mesmer) to 80 & used my instant 80 on my SPvP Thief who will be my main for WvW.

I'm primarily interested in wPvP and would like to get full Daredevil ASAP. My friend told me to get on a HoT HP train to unlock it. However, I've noticed people mentioning elsewhere that gliders/"mushroom jumping" (sic?) are unlocked as you play through HoT.

Can I hop my fresh Thief onto a HoT HP train or do I need to unlock gliders/"mushroom jumping" first? If I need to do it ahead of time, are they account-wide unlocks? My Mesmer will be my 100%er so I need to push her through HoT at some point anyway.

Lastly, how do I find a HoT HP train?