is this a low ball offer?

I have never worked in MA but have worked in NY and VT and the Northeast I think is generally a pretty well paying area. I personally wouldn't roll out of bed for that rate but if you have good housing and you really want to go there then that's your decision. There is definitely a lot more money to be made though.

But have you travelled?

and furthermore since I'm new to the travelled world it's seems like that's what most agencies are quoting me, secondly if you are traveler since I'm adding family insurance could it be easy to say that's why is so low?

I have been traveling for about a year and a half now. I don't insure anyone besides myself. I missed the part about you insuring your kids. You didn't mention how many kids. Also are you insuring a SO? I guess with insuring multiple people and housing including it may not be bad. I would recommend taking a housing stipend and finding your own housing as you can make more money that way. It really comes down to what you want to get out of traveling. I travel to experience cities that are desirable to me. Sometimes I get paid higher than others but I love where I go. Others travel to make as much money as possible and wouldn't take assignments that I would. I might not take assignments that they take based on location. So if $797 a week (post housing and insuring your kids) is enough for you to pay all your bills and have some money to enjoy the area then go for it.

Also, if you are going to being paying for insurance for the whole family, I would advise you to look into private insurance. Not only will you be likely to get better rates, you don't have to worry about gaps in your coverage due to assignment start and end dates.

That seems like a reasonable rate given you will be taking housing for multiple people and getting insurance. IF you still have to pay insurance out of that rate, I would reconsider. Also, look for housing online and see what they are paying for a stipend. If they are paying $3000 a month for a stipend and you can get a 2 bedroom for $1500..... get the 2 bedroom....

When I travelled I got meals PER DAY not per shift. If you're traveling for work, meals are deductible the entire time you are on assignment. That would be something I would bring back to them.

I would never take a rate that low.