My husband did this just 3 weeks ago. He got an old board and we scored a broken piece of formica at Lowe's for $5. He glued it on and we went to a sand hill here in Malibu - Thornhill Broome - and tried it. It did not work - it just kept getting stuck in the sand. He tried three different sections of the hill. I have video but it's not on youtube yet. I'll see if I can upload and I'll post the link and you can see how it worked.
I used to sand board with a skateboard. Attached a strap to board for the front foot to slip under and kept back foot loose. Used to cruise down a few dunes around here no problem. Just keep your weight over the tail and your good to go
Someone in NM ought to try white sands. The sand there is gypsum which is a totally different beast. Much finer. People always sled down the dunes there. And while it may be 100F out the sand doesn't absorb the suns heat so it's nice and cool on your footsies.