Raisins have natural yeast on them, and they are no doubt manufactured fairly consistently, so they are probably as reliable as you can get using naturally occurring yeast. I have also used pitted dates in the past with very good success. Natural yeast on the apples themselves, on the other hand, is more of a crapshoot. So this is probably why people have been using raisins for hundreds of years - consistent good results. But you still won’t be able to predict exactly what qualities you’re going to get unless you pitch brewers/vintners yeast.
My favorite yeasts at the moment are US-05 (ale yeast) and Cote des Blancs (wine yeast). Both are extremely reliable and fast-acting yeasts, and both finish fairly dry. The US-05 provides a sort of honey-like flavor which I find very pleasant, while the Cote des Blancs is cleaner and simply expresses the apple fruit flavor better than anything else I’ve used to date. Dry yeast is easiest to use because all you need to do is sprinkle it on top of the sweet cider, and you’re done. Dry yeast is also cheap and extremely reliable. You can try pretty much any kind of dry yeast on the market. The only dry yeast I would stay away from is bread yeast – I’ve tried that as well and it makes the cider taste bready – go figure!
As you have asked and suggested, it can be very very simple indeed to make very good cider. The most important thing, I think, is freshness of ingredients, and if you are pressing your own, then you’ve got that covered. Truly, all you need to do if you want to keep it simple is to throw in a handful of raisins, or a packet of dry yeast, and you’re done. Pretty darn cheap and easy. And while addition of yeast is optional, the only problem is a little higher chance of contamination if there’s not enough natural yeast in the cider. Personally I would hate to have to dump 5 gallons of my lovingly self-pressed cider due to contamination later while knowing I could have made an awesome cider just by throwing in $3 worth of dry yeast. So I figure it’s better to be safe than sorry and just use a pack of dry yeast for every batch. And I’ve had no complaints from me or my friends so far on my finished cider.