Where are you coming from?
In downtown Hartford there is a large park in front of the Capitol building called Bushnell Park, in the park is an old, beautifully restored carousel. About a buck a ride. There is a playground nearby perfect for your 1.5 year old.
http://www.bushnellpark.org/attractions/carousel-rides/
You might not think of it, but the Capitol building is open to visitors. Just walk in and walk around. Lots of exibits and information - free
Also in Hartford there is a fairly new Science Museum. It's a bit pricy, but good. However, it might not be worth it for a 1.5 year old. In truth it's very pricy. Check their websit for prices before you go.
http://ctsciencecenter.org/
There is a very good art museum in Hartford; the Wadsworth.
http://www.thewadsworth.org/
There is a couple of decent Children's museums within 15 minutes of Cabela's. Search the web for the Lutz and the Hartford Children's Museum.
There is a VERY cool trash and recycling museum within 5 minutes of Cabela's, and it's very cheap - $2 per person. Did I mention this is VERY cool! Big viewing windows where your child can watch the trash being dumped, the recycling being sorted, etc.
http://www.crra.org/pages/Trash_Museum.htm
If you are into history, Mark Tawin's house is open for tours.
http://www.marktwainhouse.org/
About 20 minutes away from Cabela's is the New England Air Museum. Lots and lots of planes and some decent hands on stuff for a 1.5 year - little pedal airplanes, etc.
http://www.neam.org/