Was going to reply to your post on the ASA but got pulled away and forgot about it.
Really there's not much to map. It's a small area compared to the rest of the ISDRA and pretty difficult to get lost. If you do get lost then just head north until you hit the highway - or find a tall hill and look for the power lines they run along the highway.
The basic layout is a flat section along the highway where most everyone camps. Towards the western edge the dunes end and it turns into a big flat area. To the east is the canal.
The southern border is Mexico and it can be hard to recognize - the BP dosn't like people coming back across either unless you come though an approved border crossing. I know people who've had their rides confiscated and it cost them quite a bit to get them back - usually you'll get off with a warning but one BP with a bug up his rear and your weekend could turn nasty fast

The border is really close to the highway on the western edge. Maybe half a mile....maybe. From midway campground just west of the dunes you could probably hit a baseball into Mexico if you've got a good swing and a backwind

To the east the border slopes down though and there's quite a bit of dunes accessible.
From the camp grounds if you follow the first "finger" of dunes to the east you'll find a small valley area that's the sand highway leading back to comp. The south side of the first finger is where the "first valley" is and comp is along that ridge. The western edge of that first finger has some really nice big bowls with smooth flowing lines between them. South of the big bowls watch out there are usually some pretty gnarly razorbacks - same for the south east edge of that first finger.
Past the first valley are some really nice dunes - but try to stay more to the east so you don't stray into Mexico. The sand can also get really soft back there so be carefull.
Really the only things to show on a Map would be comp, the border, campgrounds and the BIG bowl. But a map won't help you recognize the border when you're out there. The campgrounds are hard to miss...and comp and the big bowl are REALLY easy to find - just follow the traffic