Prague will still be cold in March. Especially with a child, make sure you are well covered. For a full itinerary and off beat things to do, you could read my blog where I covered everything from basic sightseeing to underground pubs, vineyards etc.
upvoteUpvote (1)messageComment
I would suggest you to visit Lipno, which is a beautiful place to visit. it will take one whole day for decent coverage. if u would like to try some ferry u can stay out. other than the cities, I would suggest one place named Divici kamen. it is quite difficult to reach this place but if u are a nature lover, it is worth visiting. Experiences: in March u will have rafting in the vlatava river and camping in the forest is very common in Czech republic. and trust me that will make ur trip. U will also find various kinds of fishing, u can try witnessing that, the kids will have fun with fishing.
If you travel with kid you need to be careful about weather. Check this guide, it can help you to decide what season is the best to visit czechia with a kid -