Popiah is available at just about every hawker centre but nothing beats homemade. It's fun to serve when lots of people are coming over for lunch. Just have everyone do the work. I wouldn't attempt to make the skins myself. Just buy them from a legit popiah skin maker. But buy frozen skins only if really desperate!
Everything can be made ahead and refrigerated so save yourself the stress and spread the work out over a couple of days!
Every family recipe is different: add tofu, cabbage, or three-layer pork.