Yes, you're on your own for other meals...I think you'll have friends out there, right? If not, maybe you can link up with friends and everyone brings something.
It's "dry camping" at JV--
very dry camping. It's a dry lakebed, with absolutely no facilities. Nearest anything is about 20 miles away in Yucca Valley or Lucerne(?).
Bring your own
everything, including water both for washing and for drinking. If you don't have an RV available, there may be a PET toilet set up but I don't know. There are no portapotties, and solid waste disposal is an issue (toilet paper does not decompose well). Do your very best to not leave any waste (food or body) out there.
As far as bringing anything, if you want to, by all means do! If you want to lurk until the last desperate pleas are issued "we
really need..." and ride to the rescue, that's cool too. Or just show up and enjoy the heck out of yourself!
If you need to keep in touch with civilization, ask where the "phone bush" is, or watch where the married guys that are out there solo head to in the evening

. It's the only (relatively) reliable identifiable cell signal source on the lakebed, but beats driving the 4 miles of dirt road back to pavement, where there's also usually signal.
If you need something, feel free to hunt me down. I'll be out there starting Friday, with my dog & possibly a teen or two, and will likely be one of very few women driving their own rigs. Mine's a white '98 two-door with stickers all along the driver's rear window and about 3" of lift (with little tiny 29" tires!).
Carol