Last weekend was my first time to offroad it. I am not an expert on sand dunes but that is my first time to take some real ones competing cruisers and patrols
Well a few tips, your Alpha is extremely powerful for the sand, so don't feel the need to floor it unless you are trying to do a steep hill climb from a dead start. Otherwise, you should be able to drive over the dunes mostly in second/third gear. Im runnig 315s and I cruise down the beach mostly in 2nd/3rd.
Run your tires at 10-12 psi, thats the best way to stop your truck from getting stuck in loose sand. Stock tires are rubbish, so you need to air down as much as possible.
Finally, if you upgrade to bigger tires, do instal a trans cooler that bypasses the stock one. The Alpha trans runs really hot in the summer with big tires (i found out when I got a scanner). Pay 1500 now for a cooler installed and save 10K for fixing a blown trans in the future due to overheating!