I walked from Orchis Massage just around the corner from Euro Inn to Phrom Phong BTS. I would guess it is another 500 metres when you reach Sukhumvit making about 1000 metres in all. It may be slighty less to Asok but I am not sure about that.
Mcintosh, if you are happy with a simple bed and crap furniture, then the Euro Inn may suit your needs...imho rooms are only good for ST...but the selection of girls is quite ok, have fun!