I would like to stay around the 3K range,
That's going to be a tough number to meet even for a rotten bay that sort of drives in a really sketchy way these days, good luck with your quest.
A bus you can use safely
this summer (even though it looks like ass and has issues) will start around $5K and go up from there, sadly others with better bank accounts have gotten into the market before you it seems. Keep watching the ads and jump (carefully) when one comes up, think about it longer than 1/2 a day and it'll be on it's way to Europe, they pay that for rusty turds as long as the photos in the ads show shiny paint.
You may find a
project for that number, but unless you work like those magic shops on reality TV your daughters will be too old to ever be seen camping with you by the time it's actually ready to go, sometimes the extra bucks up front buy more quality time now and later you'll pat yourself on the back for bucking up, you'll never get those years back later.
Don't rule out a little rust when choosing a bus to go camping with the kids either, they won't care (it's the inside and back seat that counts as well as the destination), and in a few years you can ditch it for at least what you paid and get the bus you really want after you've test driven that one and decided what you like or hate.
The #1 thing to concentrate on is the kids won't be little forever, jump now because they won't wait.