I think a part-time job would be great. It's hard to put a figure on what we do because each one of us is completely unique in what we sell and how we run our business.
There are many that do this full time and make enough to justify the time BUT these sellers are not just selling on etsy - they are also doing craft shows, traveling fairs, etc. Physically, something like that might not be possible, let alone the expense of traveling and the long hours.
When I was doing this full-time, I found myself working 12-14 hour days which I just cannot do any more. This summer I came back to Etsy after taking a year off but now I'm back in school again so my Etsy time is really limited. This also means that I'm not expecting much sales since I don't have any time to really put into it like I need to in order to be successful.
This spring I am going to graduate and will be finding a job. Etsy has never been something that I can count on to "quit my day job". But that is me. Others, including some of my friends, are successful because they really take this seriously AND put the long hours in to make it work.
So it really is up to what works for you. If you can find a job that you can handle, I say go for it.
And I understand about the physical limitations. I've been dealing with a health issue this past year and now under strict limitations from my physical therapist. It's taken some time but I'm finally able to slow down and be okay with not doing everything I want to do - instead I'm focusing on what I need to do while letting myself rest when needed.
Just take care of yourself. If the job helps you get some needed cash, you can always Etsy on the weekends and scale back a bit. Everyone has to do what worlds for themselves. Good luck :)