You can get to and from it, closest access point from the AWPR would be from the Cleanhill roundabout directly through Charleston flyover onto Wellington Road and into Altens, but not the optimum route, which would be:
Coming up from the south, heading for Westhill, completely ignore the AWPR and use the old main road to the Charleston Flyover, then divert in towards Wellington Road on the A956 and the Superchargers. Exit Superchargers, back to Charleston Flyover continue straight on to the Cleanhill roundabout on the AWPR and head north a bit for Westhill. Or you could do exactly the reverse and divert off the AWPR at Cleanhill when you are heading south, nip in to charge, then go south down the old main road.
The key thing is not to have to run up AND down from Charleston, to Cleanhill, no point. The old main road is now significantly quieter since the AWPR opened. Described as above you would add about six miles - the length of the A956 from Altens to Cleanhill - to your overall trip, and since it is nearly all dual carriageway that would be less than ten minutes ( some of it is 40mph limit ). Open Haloween-ish depending on virus I think.