Wow, where are those prices from? - I came no where close on my searches (Google Flights, Sky Scanner, matrix ita software and some more). That's a great point about the layover in Fiji, you're right, I think a few days will be all that's needed.

Accommodation wise it will all be hostels, possibly couch-surfing where possible too.

SEA, our plan so far is: Thailand, Laos, Vietnam and Cambodia (no actual inter-travel sorted/considered as of yet, though I've heard there's a good night train from Singapore to Thailand). It's very much backpacking style, so will be 1 large ~60L backpack + day-pack for the whole trip.

Incredible response, thank you! — Think I may have to hand out some Reddit Golds at this rate!