Actually, everything went very smoothly. Isaac spent the night on Friday so his parents could go out of town for a wedding. We all had a lot of fun together and the kids were totally easy-going and great.
(Notice that I made the two dinners exactly the same...I wanted to pre-empt any upset!)
Bedtime was funny. We put them to bed and could hear them talking for a while. Then, we couldn't hear Isaac anymore and could just hear Sadie whispering. Next, it got totally quiet and we assumed they had both fallen asleep. Then, I heard Sadie yell over the monitor, "Mommy! I need a change! I made a big poop!", which of course woke Isaac up. But after Sadie got changed, they both fell asleep. They were down for the night by 7:45. Not bad at all!
They woke up early but cheerful, had fun eating breakfast together and then we all went to the playground. Isaac was a great houseguest and we'd happily watch him again.
Verdict: Having two toddlers is harder than having one, but as long as you have two adults at all times, it's not bad at all. Sometimes the toddlers play nicely with each other and keep each other busy, which is very nice. However, when it's just one adult with two toddlers is something else altogether...that's a lot harder than one!