I studied abroad in Prague, and know the city well. You can arrive at 4:30am, but make sure to keep a close eye on your bag if you alight at the Hlavni Nadrazi. The locals call the park in front of it "Sherwood Forest" because so many people get things stolen.

Still, don't let it deter you. If I were you, I would walk up to the top of the hill in Letna Park to watch the sunrise. It's one of the highest points in the city and probably your best bet for seeing anything.

As for places to eat, I'm not sure you'll find much open when you arrive, so you may want to bring something with you on the train.

I hope that helps!

the train station has changed dramatically over the last few years and the Sherwood forest AladyIn London refers to has benn cut back ,there are still a few vagrants hanging about this area but they really are no bother.
There are Luggage lockers in the station on the lower level and they should be open at that time,60kc for 24hrs and you can get 2 bags in the smaller ones.You need coins for the lockers but there is a machine in the area that takes 100 and 200kc notes,there is also usually someone on duty at the kiosk that can give you change.
the station has been completly refurbished and there are loads of eating places ,not sure what time they are open but if there are tains on the go there will be a place open.
I am back in Prague towards the end of may so can check out opening times for you.
As to a place to see the sunrise, you could walk up Zizkov Hill to the big Horse monument about 15 minutes from the train station,or head to Charles bridge and watch the sunrise from there.
I do agree with Letna Park however it is my favourite spot in the city and has by far the best view in the city,the Havansky pavillion area has the most stunning of stunning views.

http://www.livingprague.com/stations.htm
just found this link with info about the train station ,might not be places for an early breakfast but the relay shops should be open and you will be able to get snacks,sandwiches and maybe even a few pastries,I can't remember if they have coffee machines but there are a few beverage machines about the train station were you can get a hot drink, don't go for the tea ,I have tried it and it is bloody terrible

unclegus - geez, you'd think I'd read and remember a name. I responded to you on 'Europe Trip' thread, and see you've already given me great advice. Thank you! Now....about that beer

Thank you both for your input. Others on this forum were somewhat negative about arriving so early in the morning. I prefer to see it as an opportunity to see/do something I wouldn't normally be awake for. But train stations aren't always in the best of neighborhoods, so wanted to at least find out if it's safe.

Thanks again!

The train station is more like a shopping mall than a transport hub,once you have put your luggage in the locker buy yourself a transport pass for the day (24hr pass 110kc) you can use it on the trams and the metro, there is a metro that can be accessed from the main foyer of the station just before the exit and the "sherwood Forest",tickets can be bought at a booth at the metro steps and if that is close then the Relay shop nearby there are aslo machines you can get tickets from but you need coins,so try the machine in the locker area to get coins if you need them.
The train station has some work going on at the moment,they have just started renovating the old part of the station ,its the old entrance hall and ticket stalls,i think it will be wonderful when it is all finished. some pics of it here.
http://www.travbuddy.com/photos/reviews/355352
seeing a city as it wakes up is quite magical and Prague reaslly is one of those cities, hope the weather is nice for you.

for beer my friend Max has a beer blog that is a real mine of information.
http://www.pivni-filosof.com/
I had a very long session at last years Beer festival with him.
he also has a great book called Prague a Pisshead's Pub Guide,there is a link to it on the blog, lots of suggested places all based on the quality of beer served.
http://www.praguebeergarden.com/
this link lists lots of great pubs by area or the beer they serve,it is by no means comprhesive but is pretty good ,also list the Beer gardens and the Brew Pubs of which i have been to most over the years.
my favourite brewpubs are U tri ruze.
http://www.u3r.cz/en/
Klasterini Pivovar
http://www.klasterni-pivovar.cz/
Jihomestsky Pivovar (its well away from the city center but worth seeking out)
http://www.jihomestskypivovar.cz/
and U Medvidku
http://www.umedvidku.cz/index.php?option=com_content&view=article&id=58&Itemid=55&lang=en
now don't get me started on the pubs.

http://www.classiccitybrew.com/prague.html
this is another good website for beer info, you can also search in it for any other places you are visiting and get info on great beers and pubs.