On the way to / from Koh Chang, you might rather like Bangkok. Take a look at the interesting (I hope) proposal how two afternoons / evenings can be spent interestingly:

Day 1:

1) Marriott Thonghlo Rooftop Bar to the west. Access by BTS to BTS Thonghlo station

Marriott Executive Apartments Bangkok, Sukhumvit Thonglor
2 Soi Sukhumvit 57, Klongtan Nua, Watthana, Bangkok 10110
02 797 0555

Dinner at a Thai Pub with live music and good Thai food with beer towers. Typical Thai local atmosphere:

I recommend Tom Yam Taley (Seafoodl, Lab Ped (Chicken Salad), Isaan Style Chicken Wings

Location to Maldvies:

Maldives Pub & Restaurant
677 Pracha Uthit Rd, Samsen Nok, Huai Khwang, Bangkok 10310
02 274 3829

Order Grab with Thonghlo Mariott. It is worth after 20:00 as you advise to avoid traffic jams.

Day 2:

Ratchada Train Market (after 18:00):
Talad Rot Fai Train Night Market Ratchada
Ratchadaphisek Rd, Din Daeng, Bangkok 10400
092 713 5599

2) seeing Thai ladyboys in Soi cowboy (after 22:00). Cacacoo bar (or something similar) at the end of the soy on the right. You will not miss because there are the most beautiful and elegant tall “women” :). So closer to soy 23 than asoke.

Soi Cowboy
Khlong Toei Nuea, Watthana, Bangkok 10110