I produce sports venues for a living, and that's similar to what you are planning and asking about.
You may need a "Permit" for the venue, but we are getting way ahead of ourselves.
Will this be an AK get together? How big are we talking here? 10 people? 100? 1,000? For 10 or 20 people getting together outside, it's usually not an issue. Right to congregate, etc. It's not a "Venue" at that point. Even with Music playing it's usually not an issue. It's just an outdoor party, unless you are disturbing the peace. Best bet, host at a State Park if you have concerns. You, as a taxpayer, own that park. A permit for the event at a State Park is inexpensive. VERY inexpensive. You already pay to support the Park in your Taxes, so you might want to call the park director and reserve a pavilion. City parks can also work, but noise is sometimes more of a problem. State Parks are easy. They are remote, and during the day music (at reasonable levels) is not an issue at all, even if you are hiring a Rock band. I've done it. No issues.
Outside of a remote park, how LOUD are we talking here? Concert levels? You need a permit. Loud enough for 30 people in a back yard or pavilion to hear? You will most likely be fine.
Food? If it's similar to a family picnic, you are OK. If you are serving to 100 people you do not know, hire a catering company and let them deal with sanitation, permits (if required), etc. Booze? That's a different story. Now you are getting into liability issues. Be very careful. I avoid any alcohol as an event director.
If you are talking about hosting this in your back yard, then it's just a matter of letting your neighbors know, warning them that there may be music for a while, and that you will shut it down at reasonable hours of the evening so they can sleep. Then you might want to inform police about an orderly and controlled party where you will have some music, and will comply if there is an issue with noise, although you, as a responsible citizen, will use good judgement.
If you are playing music to 100 people or more, and if the venue becomes large and well known, it is possible that you will be contacted by RMI (Recording Music Industry) representatives to talk to you about royalties for playing copyrighted music to the general public. This actually happened to me and other event directors that I know. There are bulldog lawyers out there that work for RMI and want to shake the tree to see if any fruit falls. I blow them off, but if push came to shove, I'd probably have to cough up some coin on my larger venues where I am playing music via a PA system to a crowd of 1,000 people. I doubt you will have this issue, but I'm just tossing it out there. You never know in today's litigious world.
So, given your quick question, these are some "potential" answers. I'm throwing darts at a board because I don't know what you have planned in your mind, nor do I know your experience or how big and well marketed this venue may become.
-Good luck!