How long would you recommend in each place? I wanted to see peoples point of view and get an idea how long different people stay in each place.

can you give us some advice on our plans,
We are thinking of..
Bangkok fly to Koh Samui Koh Tao and Koh Phangan for full moon on 27th June Gives us 17 days.
Then boat from Samui to Krabi, Koh Lanta, phi phi and Phuket end of June to middle of July. (4 weeks in total for all)

Then Should we start Chang mai - Laos - Vietnam - Cambodia- middle of July to September.
Then a week in September for Malaysia Singapore. Leaving then the 18th for Bali.

Or should we do it another way round?? Best for weather??

Should we go that route and start Chang mai middle of July or is there a way to get best weather as we are going wet season should we start Vietnam/Cambodia first and finish Chang mai?

If you want to visit Samui do it first. More likely to be drier. But if doing Krabi and Lanta it makes more sense to add on Trang islands or Phuket being the same side of coast.

Recent visitors to Samui have called it a touist hell hole.

The rain can potentially ruin it. While you do get brief downpours and hours of beautiful sun, the rain can settle in for days on end. However I have spent time on the east coast (Samui, Phangan,Tao)during those months and seen little rain. Ferry services are starting to reduce in the Andamans at that time of year although, Phuket, Phi Phi, Krabi, Lanta will still operate.

Renting a scooter anywhere could cost you your life IF you arent an experienced rider. Even that is no guarantee in Thailand. I have seen many cases of gung ho young men on Samui riding in a fashion they never would if in their home country. Many had probably never set foot on one before. No helmet, minimal clothinrig. They are their own worst enemy.
Nowhere does it say the person was covered by insurance other than that provided by the rental company. I would also be surprised if an insurance company would pay out unless the person had the appropriate kicenses and was written into the policy.

Hi,

I am travelling with Top Deck Tours - Asian Fusion. This covers a small part of Thailand, Cambodia, Laos & Vietnam.
Once it is over the tour and I arrive back to Bangkok at the beginning of January 2018 in Phuket I will stay for 2 nights and explore! I already have 2 days in a hotel here.
Is there anywhere that you do not think I should bother with travelling to. These are the places which I want to explore (however I have a flight 15 days later from Ko Samui to Bangkok then straight back home to London) So need to end there.

Phi Phi – 3 nights
Krabi – 2 nights
Ko Samui - 3 nights
Ko Phangnan – 3 nights
Koh Tao – 2-3 nights

Anyone have any tips etc?

Phuket and Krabi have a lot more to do than Phi Phi.

I would pick 4 spots total with your hotel stays. 6 is too much moving. I would drop Phi Phi and Tao. Do day tours instead.

When is Easter - As for sonkgran - here is what another site says -

"During Songkran festival (mid April), domestic travel can be a total nightmare as so many Thais are going home. Ferry services to/from islands like Koh Samui have long vehicle queues and long waits"

For a solo traveller I would choose Thailand of Peru. It feels much safer to me. It might rain in June in Thailand, but places like Koh Samui should be fine :) Besides, there are lots of seasonal activities and fruits in June.
If you insist on Peru (specifically Machu Picchu area), you might check some discussions to see what can you do there in June. I have only been to Lima, so can't help much on that...

Hostels are not the main form of budget accomm in Thailand , guesthouses and bungalows are . If you are seeking adventure be advised that places like Phuket and Ko Samui (although Westwood has an alternative cove there she likes) and Krabi are quite developed , mainstream tourist destinations and Phuket is fairly expensive.
For more tips see also this - First Timers Thread

Bungalows are operated by resorts and guesthouses are just smaller hotels.