Turtles can be left alone for a few days, although there is some risk, so it is best to have a friend and neighbor check on your turtle in your home each day if possible. You could also move the tank to a neighbor's house, but the amount of effort required plus the stress on the turtles by moving them twice in a short time makes this an unappealing option.
Some things to keep in mind:
If you are expecting very hot or very cold weather, more than your turtle could withstand, and something like the heater of the house broke, your turtle could be at risk because of the issue going unnoticed for several days. Same thing if the filter got clogged or your turtle developed a health problem or got injured somehow. In my opinion these are pretty unlikely scenarios, but something to be aware of when making your decision.
Adult turtles are well adapted to an occasional 'lean time' as far as food is concerned, although I consider it would be cruel to let it go without food for 4 days. Putting in four days of food at once will only foul the water and could make the turtle sick, without providing for it to eat on the last day, as all the food will be eaten or spoiled by then. When using an automated feeder, set it to dispense a little bit less than you would ordinarily feed, to reduce the chance of leftover food floating in the tank. A few days of relatively light meals will not hurt or overly stress your slider.