Bit of background, for years DH has always organised all our holidays. He’s a bit of an amateur luxury travel agent. Deep down I don't mind, he manages to get great deals in some swanky hotels or bargains on flights. He spends a lot time watching travel bloggers on YouTube and reading travel forums.
The dilemma is that for a significant birthday next summer he wants the two of us to tour the Far East and I foolishly said he should leave the booking to me for a change and I can sort it all out.
We fly into Singapore and out of Tokyo and will be away for 23 nights. DH suggested Vietnam, Cambodia Thailand before heading to Japan. I’m bewildered with the choice, hotels, routes, flights, trains! Help! 
Budget wise we are very flexible. The only restriction is the outbound and inbound flights as they have been booked but everything else is probably negotiable. Any ideas? I guess I'm looking for tips and inspiration. Or should I admit defeat and tell him to sort it… which I kinda don’t want to do given that it's his birthday. Plus, when it was my last significant birthday DH sorted an amazing trip to Oz, first class flights etc. so I seriously think I owe him.