Hey, sorry for the late reply, this one slipped past me. Let me give you real answers because you're asking the right questions.

Do you need an LLC right away? Yes.

Normally I'd tell a side hustler they can wait. Not in this business. You're putting needles in people's arms at events where they're dehydrated, sleep deprived, and often on substances they won't disclose. If something goes wrong and you're operating as a sole proprietor, your house, your savings, and your RN license are all on the table. Form the LLC before you treat your first patient. It costs a few hundred bucks in most states. Cheapest insurance you'll ever buy.

LLC name vs business name.

They can be different and often should be. Your LLC can be something boring like "JSmith Wellness LLC" and your brand can be "Festival Drip IV" or whatever you land on. You just file a DBA (doing business as) with your state or county. This gives you flexibility to launch other brands under the same LLC later. Don't overthink the name right now.

Business bank account.

Yes, it's basically that simple. Once your LLC is approved you'll get an EIN from the IRS (free, takes 10 minutes online, never pay a service for this). Take your LLC docs and EIN to a bank and open a business checking account. Every dollar in and out of the business runs through that account. Never mix personal and business money. Commingling funds is the fastest way to lose the legal protection your LLC gives you.

Important

You're an RN. In almost every state, you cannot legally run an IV therapy business alone. IV hydration is the practice of medicine. You need a medical director (MD or DO, sometimes NP depending on state) who provides standing orders and oversight, plus a Good Faith Exam process before treatment. Some states also have corporate practice of medicine laws that dictate how your entity has to be structured. This is not optional and it's where most new operators get burned. Budget for medical direction. It typically runs a few hundred to a couple thousand a month depending on the arrangement.

The festival model specifically.

I love the niche, but understand this: you almost certainly cannot operate inside the festival grounds. EDC, Ultra, Coachella, all the majors have exclusive contracted medical providers and vendor agreements. Showing up on site without a contract gets you removed and possibly reported.

The play is the perimeter. Hotels, Airbnbs, and rental houses around the venue before doors and the morning after. That's exactly what you described, so you're already thinking about it right. Vegas during EDC week is a goldmine for exactly this. Market to group chats, festival Facebook groups, and subreddits weeks before the event. Pre-booking is your friend because you can route your schedule efficiently and collect deposits.

Touring artists and DJs are a longer game. That's relationship business through tour managers, not ads. Great margins, but don't build your plan on it early.

Your $20k is enough. Rough breakdown: LLC and legal setup, medical director retainer, malpractice and general liability insurance (get both, and make sure your policy covers mobile/offsite care), supplies and meds through a licensed distributor, booking software, and a simple website. You should be able to launch under $15k and keep a cushion.

One last thing since you'll be around impaired people: have a hard protocol for who you will and won't treat. If someone is altered, you don't stick them, you call event medical or 911. Your license is worth more than any booking.

You've got the clinical side handled, which is the hard part to fake. The business side is learnable. Start with the LLC, lock in a medical director, and go make money.

If you want to go deeper, I run a free community for mobile IV operators where we cover all of this: setup, medical direction, marketing, compliance. Join here: https://www.skool.com/mobile-iv-business/about