OP, you may have better luck with responses if you post in a PA local board. When DD1 was small, we lived in the Philly suburbs, and she enjoyed Sesame Place much more than Dutch Wonderland. DW's sweet spot seems to be 4-7yo or so....
we just took our 3 years old and 15 month old to Sesame Place, I would have never just taken the baby, but I figured we'd bring him along and see what he could do. He had a great time. By all the bigger rides, which he could have done if we wanted him to, there were little kid areas really geared towards 1 year olds. There was a small play ground, a padded pit with padded blocks, water table zone, sprinkler, plus he also enjoyed the tea cups, hot hair balloon, and music shows. I don't know anything about Dutch Wonderland, but I'd give Sesame a shot, especially because under 2 is free.
Dutch wonderland does have a lot a tame rides for little toddlers. There may not be a lot that you will feel comfortable putting them on the ride by themselves, but there are a lot of family rides that the parents can ride along with the tots. I went there a lot as a kid and remember taking my younger brother and cousins a lot. We will be taking my 16 month old in a few weekends. I am pregnant so I don't know what rides I will get on, but from what I can remember, most of it is pretty tame, like slow moving trains and whatnot. The biggest rides they have there for the older kids are a wooden coaster, swinging pirate ship, log flume, and flying swings. They also sometimes have a diving show and other shows that you might find enjoyable.
I have been thinking of taking my 21 DD there as well. I remember going 20 some years ago when I was 6 and I think my sister was about 18 months, and there were several rides that my sister could go on with me.
Re: Dutch Wonderland w/ walking 13 month-old (yay or nay?)