Sorry I missed this one yesterday as it's RIGHT up my alley. I have run a personal chef service in CA for the past three years.
First off, unless the laws in NY are far different from CA, which may or may not be the case, your homeowners insurance will NOT cover you in ANY form of food service liability. I would get it IN WRITING from your insurance if they tell you otherwise. Homeowners insurance is just that, for a home owner. Coverage of ANY sort of commercial enterprise (i.e. you getting paid for work output) is strictly NOT covered.
Personal chef insurance is NOT all that expensive. I have a $2M/$4M liability policy for my personal chef business and pay less than $500 per year. Note that this type of coverage (PC insurance) is VERY specialized, and 99% of agents have NO IDEA how to cover a PC or write a policy that will even begin to cover this type of business for under $2500 per year. (And, even then, when all is said and done, you and your business may still not be covered correctly.)
Secondly, again, based on the Health and Safety laws in CA, which are NOT dis-similar to most states with which I am familiar, cooking in ANY not state inspected kitchen for delivery to an off site event is STRICTLY FORBIDDEN. Almost all states require that food prep be done either on the site of the event, or in some sort of state inspected commercial kitchen environment. You can get by with cooking in your outdoor smoker, or BBQ equipment, but all of your prep work must be done either at the site of the event (following HD regulations), or in a commercial facility. Again, in most states, you CAN prep in a commercial facility, transport the food to the event site for cooking on your equipment, and then do the food service work at the site of the event. An example of this would be prepping your butts, chicken, and ribs with rub etc. would be done in a commercial kitchen. You could then refrigerate the prepared product in refrigerators or in ice chests with thermometers to confirm the internal temps of the coolers. The product could then be transported in the coolers to the site of the event, and cooked on site. Once cooked, the food can be processed and served on site, and you are still legal. Of course all along the way, you are required to adhere to the HD requirements in place for the jurisdiction in which you are working.
To answer your original question as to how much to charge, I would generally charge somewhere from $1700-$2500 plus the actual cost of food and supplies for this sort of event. (I give each client a "not to exceed" budget estimate for the cost of food and supplies, and I guarantee that rate. The client gets the actual receipts, so they know I'm not skimming them on those dollars. Fact is, 99% of the time, I come in under budget on the cost of food and supplies.) For that fee, I own the responsibility for shopping and getting all of the food to the event (liability requirement for my insurance), and having it all cooked, prepared and ready for service. I clean up and deal with the food related trash at the end of the event as well. Tables, service equipment, dishes and silverware are all at an additional charge. If the client wants actual table service (i.e. with wait staff) that also is an additional charge. For 150 people, I normally will use 1-2 additional people besides myself, and that staffing IS included in the base price quoted above. (again, my insurance requires these people to be on my 'staff'.) Oh, and just for reference, that price is NOT considered to be high for this sort of service. And, yes, I get this sort of business on a regular basis, though I admit that events of this size are NOT in my 'sweet spot'. (I generally specialize, by choice, in events for fewer than 50 people.)
I'd be happy to address any questions you may still have. I will always be up front that what I know to be true will be from the rules and laws I have to follow in California. I may, or may not, know what the rules and laws of other states, and will freely speak to that whenever I address a question. (If I KNOW the law in your state, I will tell you. If not, I'll tell you that, too.) As a member of a national professional chefs association, I have access to the practical experience and knowledge of my peer personal chefs from all over the country. So, often times I can ask them to share with me the challenges they deal with, and what their rules and laws may be.
Hope this helps.