I’d drop the DD options, so much more power available w/ belt/gear drives.
Your first job is to pick out a deck/enclosure that will fit your battery and electronics.
Idk what “long” range is to you, but you could be shooting for anywhere from 15-25AH, which might have to be a double stack configuration depending on how big the deck is that you choose and which cells.
The haggyboards drive setup is a good choice, if a little pricey. You can spend a few more $$ and get an Avio AT gear drive as well.
W/ your budget, I’d buy:
$150 Landyacht Evo 40
$150 eboosted DS enclosure
$4-700, depending on how it gets built: 12S8P 30Q
$675 ($910 w/ gear drives) Haggyboards complete drive system
$100-200 Smaller things like metr Pro/bluetooth so you don’t have to open your enclosure to mess w/ software, remote of your choice, grip tape, misc hardware, etc
If I wanted to spend a little less and have a sweet carver style board, while sacrificing some range, it might look like this:
$200 EBS deck+enclosure
$4-600 12S6P VTC6
$200 MBS matrix II trucks
$50 motor mounts
$100 2x 6384 motors
But you could easily spend a few more dollars and swap out the deck/enclosure for a Trampa + DS for $125 more to fit a 8p pack in it.
Oh the wonders of DIY, you’ve got some decisions to make.