I would assume it will be Soi 96. I know your wife is Thai, but it's only a 5 minute walk from there (if you can cross the road).
Traffic will be busy, so the pedestrian lights are usually switched off (when they're needed most). Walk to MV and cross there, where the guards will help you.
An alternative to taxi or walking would be the 10 Baht Songthaew, which goes right past the bus station and dentist,