Speaking as someone who walks their dog up and down S Regester literally everyday, my advice would be that it's mostly fine but gets spottier the further north you go. There are some vagrants and some drug activity (not unusual for broadway area tbh) and I have known female friends who have been harassed (never robbed or hurt but definitely spoken to uncomfortably) further north on Regester.

Regarding parking, it's decent for the area, though do note that some regester blocks do not actually have parking. Also you need to be, or will quickly become, a master parallel parker because the lane is so narrow between rows of cars that it can be tricky to get the right angle.