Dan, nice report and sound like a good trip.

Just a few added comments to some of the other questions.

You can walk from the Hilton to either Wasclavske nam (the main sq.) or namesti Republiky in about 10-15 mins. You could have walked to the train station too if it is not so convoluted since there is not a street / path on that side of the highway.

If you have only one day, then a long walk from Vaclavske namesti to Starometske namesti (old town sq) Jewish cemetary to Charles Bridge (and down to Kampa Park if you have time and weather is nice) to Mala Strana and up to the Castle and walk around the castle area is what I would suggest to get a flavour of Praha history and architecture.

I worked in Praha from '92 and '98 and would suggest people go a little outside the city center if you have more time. I went back May '04 for a weekend and have found the prices have gone up significantly in the tourist center and I was seeing mostly tourists in the city center which does not give you the full picture of Czech life. There are some nice local pubs in areas just a couple of subways away such as Nam Miru or Namesti Jiriho z Podebrad where it is still more locals. They are called Pivnice usually and beers will be a dollar or less and you might strike up an interesting conversation with a local.