Here I'm going to explain the things I figured out the routes, on the go, during my second trip to Thailand.
Since I was traveling during the supposed peak time in Thailand, I was suggested I better get the Thai visa from India itself rather than going for Visa on Arrival which might cause delay at Airport though Thai government had announced fee waiver for VOA this year. Thai visa is easy to obtain from India through VFS in Bangalore by following the process described here http://www.vfs-thailand.co.in/Chennai/tourist.html.
The process was extremely quick(unbelievable) and easy at VFS office located at Thailand Visa Application Centre, Global Tech Park No: 11, 1st Floor, O Shaughnessy Rd, Langford Town, Bengaluru, Karnataka 560025. Laptops/CDs/Pen drives are not allowed inside the office but there is a outside store which has locker facility for use per hour. The current rate is 70 Rs. per hour. One additional detail is VFS office does not accept credit card for visa fees, only Cash can be accepted(its 2019 guys!!). I was the first one in as I reached there at 8 AM and came out in 10 minutes max. I opted to receive my passport with visa stamped through blue dart courier and I received it exactly on the 6th working day.
My trip involved going to Bangkok, Surat thani, Koh Phangan, Ao Nang - Krabi, Chiang Mai, Pattaya, Bangkok in that order. In my earlier trip, I had explored little bit of Bangkok, Krabi, Phi Phi Islands in a 7 day trip.
I needed to figure 1) How to go from Suvarnabhumi Airport(aka BKK airport) to DMK airport, 2) How to reach my Hug hostel Rooftop in Chiang Mai from CNX airport, 3) How to reach Pattaya from BKK airport and then reach Nonze hostel in Pattaya, how to move around in Pattaya and 4) how to get back to Bangkok from Pattaya, 5) how to reach BKK airport from Nana BTS station and I did little prior research in figuring it out.
1) How to go from Suvarnabhumi Airport(aka BKK Airport) to DMK Airport?
I followed the instructions in this blog http://www.pausethemoment.com/bkk-to-dmk-for-free/ for going to DMK airport from Suvarnabhumi Airport(BKK). I had about 7 hours to catch the next flight at DMK to go to Surat Thani which was more than sufficient time. The free shuttle from BKK airport took about 50 minutes to reach DMK airport.
2) How to reach Hug hostel Rooftop in Chiang Mai (CNX) Airport?
Hug hostel Rooftop is located in Old city Chiang Mai, near the Old city North Gate stop. Getting to old city from Airport takes about 15 minutes by taxi. The Chiang Mai airport has taxi that charges 125 THB to take to old city. Hug hostel Rooftop is an average hostel, the bathrooms were spacious but the sharing rooms were dorm type beds with little privacy. Since it had one single door for all the dorm members, there is a chance that you might be disturbed a lot during night or the time when you need a little relaxing. Grab taxi works in Chiang Mai but the price can vary depending the time of travel so early or late night taxi might be expensive. for eg: My early morning taxi to Airport from the hostel cost me 190 THB.
Old city North Gate stop is the place to get Songthaew (Red taxi) that takes to popular places like Doi Suthep temple located on top of mountain charging 60 THB one way.
3) How to reach Nonze hostel, Pattaya from Suvarnabhumi Airport?
At Suvarnabhumi Airport, go down to level 1 (Public Transportation), look for Exit Door 8 and catch a bus to Pattaya for 120 THB. There is a bus to Pattaya every 1 hour and seat numbers are assigned in the ticket itself. Here is an excellent blog visually describing the step by step process to get to the ticket counter https://www.markblackard.com/how-to-get-to-pattaya-from-suvarnabhumi-airport-for-120-baht/. There are 5 bus stops in Pattaya depending on where you want to go to Pattaya. I had booked at Nonze hostel, Pattaya. So I got down at the 3rd stop which is South Pattaya intersection, walked across the bridge to get to the South Pattaya road. I took a Songthaew(Blue taxi) for 10 THB which dropped me on the Pattaya Soi 2 road running parallel to the Pattaya beach road.
4) How to reach Bangkok from Nonze hostel, Pattaya?
I took a bike taxi to reach the Pattaya AC bus terminal, cost me 100 THB. The AC bus terminal in Pattaya is located on the North Pattaya Road and buses run every half an hour to Bangkok. No prior reservation is required and it costs 108 THB to reach Ekkamai bus station in Bangkok. This blog describes the AC bus terminal in North Pattaya road http://www.bangkok.com/pattaya/magazine/pattaya-bus-terminals.htm. The Ekkamai bus station is close to Ekkamai BTS metro station.
If you want to reach BKK airport, you may need to catch the bus terminal located at Near Food Mart Supermarket, Thappraya Road, South Pattaya.
5) How to reach BKK airport from Nana BTS station?
There are 3 days BTS metro passes available if you plan to roam around Bangkok. Since I was not staying for 3 full days I opted for a regular metro card that cost me 200 THB out of which 100 THB is not refundable and 100 THB is a usable amount for metro travel. I took a metro from Nana BTS station and took a train towards Mo Chit BTS station, alighted at Phaya Thai BTS station. Then I followed the directions by walk to go to Airport Rail Link(SRTET City Line) which required a token of 45 THB to take to Suvarnabhumi Airport(BKK). This total journey takes about 40 minutes.
Note: All of these journeys and connections were easily possible as I had very light luggage.