With a Huge size and an 8 Dex, its Rogue potential is decidedly limited. Hide/Move Silent is really off the table, and while you might think he could just jam trap mechanisms with his sandy body, there's nothing in the rules to actually support that.
And yes, this is the campaign where we were recently in Egypt/Ethiopia. That's where he was created/Awakened, for a specific task.
And that's where the construct is and will remain. Other players/DMs said no to having him come along, not wanting to add to the roster.
Ironically, three of these took the Leadership feat for their characters, and one is currently playing a character that was the Cohort of his previous character. A fourth has a Tiger as an animal companion, and wants to increase its size to Huge as part of its advancement.
We, at least in theory, had something like 40 people following us around on our adventures.
While it's interesting to speculate on advancement for such a creature, the fact is that there's no mechanism in the rules to allow him/it to earn any Exp unless my character spends a Feat to take him as a Cohort. Neither Hirelings nor Followers get any Exp, by the book.
As for uses: He moves faster than a person on foot, but slower than a horse (40 base), and while his weight isn't specified, dry sand weighs in at about 100 lbs per cubic foot. Water weighs a bit under 64 per cubic foot, so call his weight about 1.5 times the weight of a flesh and blood creature of similar size. In other words, more than a wagon can think about carrying, and more than any small to modest boat can manage.
On the plus side, his heavy load is about 5,000 lbs, so if you cast an Overland Flight spell on him he can not only keep up, he can play the part of a DC3 cargo plane.
He has a Burrow speed of 20, which has its uses as well.
In combat, he has a 15 foot base/reach and a 20 Strength. +6 BAB, +9 full attack (6 BAB + 5 for Strength, - 2 for Size). Spells like Greater Magic Fang could, at our level, bump that as high as +16, which almost makes him playable.
He has a special attack (Engulf) that can be avoided with a DC 19 Dex save. The attack provokes Attack of Opportunity though, and with an AC of 13 he may end up hurting himself more than he hurts them.
Ultimately, while there are things that could be done to enhance the creature, they amount to souping up a flat bed truck and expecting it to compete at Indianapolis. It might be possible, but it's really not worth the effort.
My character's concern over his creation is more an RP thing than anything else. And I've been told to forget it.
But that's okay. One of the DMs has been talking about "The Lost World", that part of Africa where the dinosaurs roam. If he runs us there, I'll shock the hell out of him by using Limited Wish to Awaken a Megaraptor or a T-Rex, and have that as my character's new mount. <Evil Grin>