Take it gradually and see if that is what you want to do. I can tell you right now those 20-30 people gigs aint got nothing on a 200 people gig. You start running out of food or a full pan gets knocked over by a drunk, then the gig goes to hell in a hat basket. Nothing like a little complications to make it all fun.
I could never do catering for a living, it doesn't pay enough, but thats the beauty of it, I can cater and still have fun. I try to do one or two jobs a month and i get my fix. You might find this will also work for you. I could do a restaurant for a living, but then I would try for OPM.
There are some of us here that can give you some good advice. Just keep it simple to keep it fun. Good luck and keep us posted.