I spent 2 months backpacking around Thailand, Cambodia, Laos, Vietnam and Bali and this is the route I took. I booked most of my transport through 12go.Asia, most of my flights through trip.com and most stays through hostelworld.
Thailand
3 days: Bangkok
Stay: Wild Orchid Villa Khaosan
Things to do: Visit temples, Boat trip down the river, Tuk Tuk ride, Night out on Khao San Road, Cooking class at May Kaidee’s Cooking School (link)
Overnight train to Surat Thani and bus to Khao Sok
3 days: Khao Sok National Park
Stay: Khaosok Eco Raft
Things to do: Sunset boat trip, Kayaking, Tubing
Bus and ferry to Ko Pha-ngan
4 days: Ko Pha-ngan
Stay: Sarana Bungalows
Things to do: Full Moon Party in Haad Rin, Visit beaches and waterfalls, Muay Thai class
Ferry to Koh Samui
3 days: Koh Samui
Stay: Timeless Hostel
Things to do: Samui Elephant Sanctuary
Ferry, bus and ferry to Koh Phi Phi
5 days: Koh Phi Phi
Stay: P.P. Palmtree Resort
Things to do: Fire show at Carlito’s Bar, Walk to Phi Phi viewpoint, Boat trip to Maya Bay, Monkey Beach, Shark Point and Bamboo Island, Get a tattoo
Ferry, bus and overnight train to Bangkok
1 day: Bangkok
Stay: Grand Mercure Bangkok Atrium
Things to do: Rooftop bar at Carlton Hotel Bangkok Sukhumvit
Fly to Phnom Penh, Cambodia, and bus to Kampot
Cambodia
2 days: Kampot, Cambodia
Stay: Onederz Kampot and Arcadia Backpackers & Water Park
Things to do: La Plantation pepper plantation, Enjoy hostel’s water park
Overnight bus to Siem Reap
2 days: Siem Reap
Stay: Onederz Siem Reap
Things to do: Angkor Wat tour, Night out on Pub Street
Fly to Pakse, Laos
Laos
2 days: Pakse
Stay: Pakse Hotel
Things to do: Waterfalls, coffee plantation and local village tour
Fly to Vientiane
1 day: Vientiane
Stay: Sailomyen Cafe and Hostel
Things to do: Visit Patuxay Monument, Tipsy Elephant rooftop bar
Train to Vang Vieng
4 days: Vang Vieng
Stay: Vang Vieng Freedom Backpackers 2
Things to do: Hike to Nam Xay Viewpoint (disclaimer: this is challenging and you will be climbing with your hands right at the end), Kayaking or tubing on the river, Hot Air Balloon ride, Visit the blue lagoons
Train to Luang Prabang
2 days: Luang Prabang
Stay: Sunrise Riverside Pool Hostel
Things to do: Night market, cat cafe, tour to Kuang Si Waterfalls
Fly to Hanoi, Vietnam
Vietnam
2 days: Hanoi
Stay: Nexy Hostel
Things to do: Ha Long Bay tour, try authentic Pho
Fly to Bali and taxi to Ubud
Bali
3 days: Ubud
Stay: Komaneka at Bisma Ubud
Things to do: Cooking class at Pemulan Farm, tour of rice terraces
Taxi and boat to Gili Trawangan
3 days: Gili T
Stay: Kardia Resort Gili A Pramana Experience
Things to do: Rent bikes and swim with turtles
Boat to Nusa Penida
3 days: Nusa Penida
Stay: Coco Resort Penida
Things to do: tour to see Kelingking Beach, Angel’s Billabong, Broken Beach and Crystal Bay, Take a day trip to Nusa Ceningan and visit Sea Breeze Pool, Bar and Restaurant
Boat and taxi to Canggu
4 days: Canggu
Stay: Sedasa Lodge
Things to do: Finns Beach Club, Shopping, Brunch at Copenhagen