Larger pots should be fine if you'll be gone just two or three days, especially if rain is predicted. Give them a good soaking before you go. Set up a contingency plan for small pots that usually need daily watering.
Move portable planters and hanging baskets to a shady spot (pots dry out faster in sun) protected from drying winds, and cluster them so they benefit from the raised humidity of huddling.
Purchase one or more container irrigation kits (sold at garden centers) and enough tubing to reach all your pots. Once it's set up, a drip system is the most efficient way to deliver moisture to numerous pots.
Use a hose faucet timer to set how often and how long you water. (Test it before you leave to determine the best plan.) Some digital systems can be operated remotely with a smartphone or computer.