My husband and I go with just our 1-year-old, and we use rider swap a lot. That said, we will use single rider instead if we can, so we honestly didn't use a lot of FPs last time, not as many as I thought. A few personal notes from memory:
-I don't quite understand the previous poster not using rider swap because her LOs would be unhappy to not ride a ride they were waiting in. With rider swap, the kids would never wait in line. The kids actually don't really have to know the other parent is going on a ride. My DH would just ask for a rider swap card outside the ride from the CM and we'd go do other things while he went on, and vice versa. Sometimes the CM would need to see me as the "other rider" (we could wave from a distance, we found), but usually they just handed over the card to him. (I could be misunderstanding the last poster, though.)
-The single rider line for RSR is unpredictable. Sometimes it's great, sometimes it is long-ish. I'd get a FP for this if you really want to do it. But it also does't count against your FP totals, so there's no reason not to get them if you get there early in the day.
-WOC FP also doesn't count toward your current/total FPs. Based on advice, we waited til around 11am to get ours, and we got in the middle section. We got there around 10mins before showtime, and while we had a fine place to see the show, we probably should have gone a little earlier to get really good spots, even with the FP (since they are by color coded area).
-I wouldn't (and didn't) bother with FP for California Screamin (which we love). The SRL there was almost non-existent, in part because it's actually VERY hard to find (ask a CM). The DH and I would go one after the other, over and over again with hardly any wait at all. We'd take our son to the viewing area to watch the other person "take off" and then we'd tag the other person in and go again!
-If the Matterhorn is your thing, I would recommend getting a FP instead of Single Rider. The SRL is PAINFULLY slow and frustrating on there, in my experience. (Obviously, the previous poster had a different experience, though, so it could be luck of the draw.)
-For reasons I don't remember now (I think they shut down for a time?) my husband did Indiana Jones via single rider, and I did it via FP at a different time. They ended up being around the same wait (20mins). Also, DH said the single rider line skips some of the cool queue stuff, if that matters to you.
-There are ways to use the rider swap WITH FP to your advantage. In short: You can both get a FP for a ride, and then use the rider swap to basically get two more FPs. We did this a few times on rides we love, like TOT. DH would go with his FP and get a rider swap card, while I fed the DS or walked around. (We love the bench area where the Red Car Trolley stops next to TOT for snacking and people watching!) When he was done, I could go back on with the rider swap. Then we could use my FP and do the same thing again.
Alternatively, it can allow you to hold more than one FP. So you could get a FP for TOT and do the rider swap, and also have a FP for Soarin at the same time. Here's a blog post that explains it well:
http://blog.touringplans.com/2010/12/17/fastpasses-and-the-rider-exchange-a-powerful-combination-2/
I think TP has the BEST and most useful FP advice overall, so I would definitely read through all of what they have to say:
http://touringplans.com/disneyland/fastpass
