For ATMs I would recommend the NCB machine in the Sunshine Plaza (by Hi-Lo). Less potential hassle than the Scotia Bank by the roundabout and I find the fees to be cheaper.

Personally, I would skip Mega Mart in Mobay, and just stop at the Hi-Lo and the ATM in at the same time. However, we stay on West End so it is conveniently on the way to our to hotel. If they are staying on the beach, it will be a few minutes out of the way (but still might be quicker than a Mega Mart stop).