I was in Prague in October and one thing I would struggle to do is find something that is NOT touristy. First of all, I enjoyed Prague. Definitely, it was worth the visit. But my experience was that it was spilling over with tourists. So I guess I would advise you to be prepared for that. I believe I read that since it is one major European city that has only relatively recently been freed from communism - the tourist are flocking in droves.
Everywhere was a shuffle of people with their guidebooks and maps.
Having said that, put your patience hat on and really enjoy the cathedral, old town square, the beer, the food, St. Wenzelas Square, the parks, the Jewish quarter, the castle...all of it.
If you find something that gets you away from the tourists within the city of Prague - let me know! :)
It rained a lot and was cold when I was there, but that is luck of the draw I guess. You might have sun and mild temps.
We ate more times than I care to admit in the Old Town Square. Sausages, potato pancakes (too greasy), baked cinnamon pastries (yum!), mulled wine, beer, roasted pork. It was inexpensive and very good. Plus the ambiance of the square is all around.
But we also ate at a Pils Urquell restaurant. I had a roasted chicken with mashed potatoes and it was FABULOUS! I vividly recall how good it was. There are multiple locations for this restaurant around Prague, so you will probably run into it.
And if you go to Restaurant Mediviku you can get the original Budweiser. The Beef Stroganoff was superb and the Pork Knuckle looked delicious.