Assuming that its for 1 month and your main objective is mongering, but also some sightseeing, then a potential itinerary could be:
Fly into BKK and 1 week there. There's lots to see and do in the day and at night.
Week 2 - taxi//bus/van to Pattaya. Its mainly mongering. Lets face it, nobody goes to Las Vegas to look at artwork.
Week 3 and a half - back to BKK for a few days there and then fly up to Chiang Mai for 1 week. Chiang Mai has a smaller, but active LB scene around the night market and there is a lot to see there. Its a good place for R&R in the mountains. (The LBs from the north are also very different from their Isaan 'sisters').
Last few days - fly back to BKK. Say goodbye to all the teeraks that will miss you and love you forever and buy the souvenirs, get the last massages etc.
Internal flights in the LOS are (were) very good and are (were) very cheap. Thailand is a big country, so its the best way to go. Avoid driving in the LOS if you can.
If you'd prefer a beach holiday instead of mountains, then substitute Phuket/Koh Samui/Koh Samed/Koh Chang etc. for the Chiang Mai week. The beach resorts have less LB options and your enjoyment will vary greatly based on what time of the year you go, whereas BKK/PAT/CNX are more all year round.
Most of us have been locked out of the LOS for 18-24 months now, so all of this advice is based on the past experiences. The assumption is that by 2022 things will be back to as they were, i.e. flights are still cheap, there are still girls left in BKK, PAT etc. Somehow I think that some things will never change. LOL.
Phuket's LB scene is small (and smaller than it once was); the scene in Koh Samui is minuscule. Samui is a lovely place for some R&R but a lousy place for chasing LBs, IMHO.
That said, both Phuket and Samui are lovely places to hang out on relatively uncrowded and unpolluted beaches (unlike Pattaya), so if you want a little time to de-stress and just chill, both are fine options.
If it's your first trip, you probably want to keep the itinerary simple. Maybe 75% Bangkok and 25% Pattaya. Or the opposite. Up to you. There is loads to see and do just in Bangkok for a first-timer.
I think most guys here go directly to Bangkok from BKK airport and make their jaunts elsewhere later in the trip. On most trips I spend a month. It's usually 2 weeks in Bangkok, then 1 week in Pattaya, then back to BKK for another week. Sometimes I go with my girlfriend to visit her family in Lampang for a few days. Other times we go to Hua Hin or Chiang Mai instead, but I always stay "headquartered" in Bangkok.
No need to mess with U-Tapao because BKK or DMK airports are only about 2 hours from Pattaya and you can fly anywhere from there with many more schedule options.
I don't care for Phuket and the LB scene is fairly minimal there anyway. I have never been to Samui, maybe others can help you.
Let's presume everything is normal in Thailand and domestic flights work normally. I was thinking about the best way to travel in one month's holiday to all these places.
Because let's face it, these 3-4 places are where the ladyboys are. Mostly in BKK and Pattaya, yes. But for a holiday it would be nice to visit Samui and Phuket too. If Phuket is no go or not worth the effort, we can drop that.
First International flight to BKK, obviously. But where from there?
There is an airport near Pattaya, the U-Tapao. ? but I think you can only fly there from Samui or BKK?
All the 3 or 4 places are in a kind of " triangle" considering the geographical location.
I know maybe it's easiest to spend a couple of nights in BKK and take a taxi or minibus down to Pattaya and go back to BKK and flight to Samui.
Or from Pattaya to U-Tapao to Samui and back to BKK? There are many options.
Short holidays like 2,3 or even 4 weeks you tend to not want to travel too much It is just a waste of time to sit in an airport or minibus all day.
Just asking what the wisest and most cost-effective route to take is?
Be free to speculate all the main destinations freely and maybe even visit-worthy places during the travel.