In the past month I've gained a lot of respect for other stay at home parents, and have begun to see the challenges. I'm blessed in that I had some advanced preparation -- for almost a year now I've been splitting shifts with my wife, taking care of The Lad while she was at work, so I didn't just step off into the deep end (more like the Marianas Trench!). But even though I was putting in almost as many hours alone with him then as I am now, there's a huge difference between that sort of arrangement and taking on the role of SAHD.
For one thing, the loss of adult socialization cannot be overstated. Oh, man, does it get lonely. The poor grocery clerks get an earful. I plan to do some research on playgroups in this area. Finding fellow parents with whom to socialize has been more challenging that I first expected -- there is a sort of reverse gender bias, and while people smile approvingly of my choice to be a SAHD, a man alone at a park with a toddler is not as quickly welcomed by the rest of the parents there as a mom would be.
Then there's the twin demands of childcare duties and housekeeping. Some chores are of a nature that if they're done while he's awake, he will get in the way, or cannot safely be done with him around. Examples would be laundry (try keeping a pile of folded clothes folded with an active toddler around) or cleaning toilets. These are best done during naptimes. Other chores are noisy, and can only be done when he's awake. Problems especially occur when a chore arises that fits in both categories -- noisy AND unfeasible in his presence.
Naptimes themselves are a challenge, since they are only semi-structured. I know roughly what time each day he'll need one, but am never sure how long it will last.
This transition has been a challenge, and I'm sure it will continue to be so. One issue I'm starting to see is an attitude creeping in to my wife's thinking that seems to expect me to be responsible for all domestic duties, even when she's home from work. It's an attitude for which our society is critical of men in traditional households, but I think it's just human nature. My wife has acknowledged the shortcoming and is trying to avoid it, but it still pops up from time to time.
Now if you'll excuse me, someone's up.