Yes of course you can exchange any currency anywhere in Bangkok and mostly the currency rates do not vary. There are so many places to eat street foods in Sukhmvit and it also depends where your hotel is. but you can find street foods almost anywhere in Sukhumvit.

I go to HealthLand. There are couple of locations. It is legit place. The prices are reasonable. You can pay with credit card.

Hi Jacky, yes I can. In can recommend Nuch Massage on Soi 24 (BTS Phrom Phong). I’ve been coming here since 2011. They do a very good manicure and pedicure. Good prices (300 THB for mani or pedi as of April 2018) and hygienic. They use clean instruments for every customer. They mainly cater to locals (as in Thai with money to spend), but are tourist friendly. No need to ask at hotels if they can fix you, as they will probably have their own spa with very inflated prices or recommend one that does the same. Hope this helps you!

Think I have said this before I have started to exchange my money in Thailand far better rate I use Super rich in the BASEMENT OF Bkk Airport will only exchange mint £50 and £20 at best rate 10 mins walk approx £160 more in my pocket on wot others were offering (changing £3000) can be difference between nice room or Very nice room

Sukhumvit is a wonderful area. I have never photographed anything in the area that I thought was "ugly." There are wonderful things to see and learn all along the Sukhumvit area. Ugliness is in the eyes of the beholder. Perhaps ugliness ideas come from within a persons own demeanor...

I wish you a wonderful trip. Yes, all along Sukhumvit are numerous shopping opportunities and department store areas, especially in the Sukhumvit 24 area where you will find Emporium and within many places to eat, watch movies, and much more. I recommend. Also, depending on the time, you should give yourself plenty of time to get to the airport, but know that there are mass transit systems such as Sky Train that could allow you to get out of the city to a place much easier to catch a taxi to the airport, such as going on Sky Train out to On Nut then taking a taxi, etc.. Just check the local information before deciding when you will leave and where you will catch a taxi. You could also use the Airport Train if it is operating... Check local listings...

If your planning on staying for a few weeks or more I would say to buy the cheaper clothes that the Thai people buy. But they also have some fab clothes that are quite a bit more expensive but they will last a lot longer. If you go back to the same store or open air market a few times you will find the owner will give you a discount bigger than the normal 10% they give everyone (if you asked for one). It also depends on how much money you have to spend.