Hello!

I realize I risk the usual internet forum barrage of Devil's Advocacy replies in posting a "hello" with some questions, but here goes:
 
I am a paramedic in MA, living in Cambridge. I have a few great locations nearby that would be a great place to set up a hot dog push cart, and am wondering if anyone here in the area knows some of the more sticky ins-and-outs of setting up a push cart in Cambridge.
 
-Do they allow push carts at all? 
 If so, are they allowed on sidewalks? Who do I ask about that?
 
I see a handful of food TRUCKS over by MIT, but haven't seen any push carts.
 
I've gleaned from reading here that I'll need a state hawker's/peddlers license first, then a city license, board of health inspection and sign-off, and probably a fire dept sign-off as well. I'd need to be set up to pay MA food tax as well. I'd have to set up as a sole proprietor.
 
What else?
 
How did you guys/ (and gals,) get set up with a commissary partnership? I don't know the first place to start there. 
 
Still, I'm intrigued with the idea of doing what it takes to be set up and do this for a living. Even with it's sundry requirements, it still looks like a fun way to make a living. I spent two summers working at carnival counters as a barker back in the early 90's, and loved it. I do realize that there is SO much more to getting it going than just showing up and selling wares, and I welcome any and all info.
 
I plan to just sell hot dogs, sodas, water, chips and maybe some pre-packaged cookies. (the kind of cookies that are labelled for individual sake, of course,). 
 
I'm sure I'll be having plenty of correspondences with my city BoH and offices, but I wanted to start here first, just to see what those "in the know" had to say.
 
Best,
Scott