In Thailand we had consistently double room with private bathroom and free Wi-Fi.

Central Thailand
Bangkok
BB (Best Bed) House 2
45 Soi Ram Buttri, Pranakorn, Bangkok
Tel. 02 629 2529
THB 580 (A/C), 04/2015
little, clean rooms at 3. AND (relatively quiet), clean, friendly staff, lovely roof terrace to sit
IMG_6476 (Medium)

SidaRe Bed and Breakfast
127-129 Soi Udomsuk, Suthisan Road, Bangkok
Tel. 02 277 2876
THB 540 (A/C), 05/2015
simple room, Near Metro

Kanchanaburi
Tamarind Guesthouse
29 / 1 River Kwai Road, Kanchanaburi
THB 600 (A/C), 04/2015
small room in 1. AND, clean, quiet location right on the river, Laubengang
IMG_5821 (Medium)

Trat
Pop Guest House
Th Thana Charoen 1/1, Trat
Tel. +66 39 51 2392
THB 450 (A/C), THB 350 (Fan), 05/2015
simple room, high noise level

Ko Mak
Pano Resort
44 Moo 1, Tumbon Ko Mak
Tel. 086 022 8449
THB 650 (Fan), 05/2015
Comfortable double bungalows on stilts, Mosquito net available (necessary), secluded location at the Wadden Sea
IMG_7205 (Medium) IMG_7201 (Medium)

Northern Thailand
Chiang Khong *

Rimnaum Guesthouse
right on the river
BEFORE 500 (A/C), 07/2015
Small, simple room with views of the river, Hotel exchange for bedbugs and unfriendly owner

Rimnaum Hotel
50meters from Rimnaum Guest House on the river on the other side of the street
BEFORE 500 (A/C), 07/2015
Simple, clean room, Coffee / tea for free
*Overpriced accommodation

Chiang Rai
Orchids Guesthouse
1012/3 Jedyod Road, Chiang Rai
THB 350 (A/C), 07/2015
Clean, small rooms in 1. AND (Laubengang); Free Coffee, Tee, Bananas

Baan Bua Guesthouse
879/2 Jedyod Road, Chiang Rai
THB 450 (A/C), 300 (Fan) 07/2015
Simple Room, too hot, too expensive, bad wifi, beautiful garden

Chiang Mai
Kavil the Butterfly sthouse 2
27/5 Self Moonmaung 9 | Old City, Chiang Mai
THB 400 (A/C incl. Fan) 07/2015
Simple, quiet room in 2. AND, nettes Personal

Mae Sot
Arissa Hotel
Intarakree Road Soi 5, Mae Sot
THB 690 (A/C) incl. Breakfast Buffet
Clean, large rooms with refrigerators and private balconies in 3. AND, too expensive
IMG_9888 (Medium)

Phannu House
563/3 Intarakeeree Road, Mae Sot
THB 500 (A/C), 400 (Fan) 07/2015
Clean, cozy room with a refrigerator and a private balcony in 2. AND, quiet, centrally, nice owners, Scooter Rental THB 150 / Day