Fares are indeed cheap in the Czech Republic compared with the UK.
Many of the fares shown on the CD website are available at the station, but they have various promotional fares, which have varying requirements.
Rovers are a good way of getting around - and far simpler than buying lots of tickets, especially if away from big cities where English is less likely to be spoken by staff. If using Prague main station (Praha hl.n.), I would recommend getting tickets from the "International and Other Tickets" section of the main booking office, as all the staff speak English.
There are two main types of rover ticket:
- one person ticket for any day of the week (with no time restrictions, unlike the UK)
- group weekend ticket, valid for up to two adults and three children (no need to have any children with you), which costs only a little more than a one person ticket, but only available on weekends and public holidays.
Both types of rover are available covering the whole country or selected regions. You can combine two rovers for greater coverage, but if you need three, you are probably better off with the whole country ticket.
One person day rovers:
http://www.cd.cz/vnitrostatni-cestovani/jizdenka/jizdne-a-slevy/-9533/
Group Weekend day rovers:
http://www.cd.cz/vnitrostatni-cestovani/jizdenka/jizdne-a-slevy/-9534/
The Terms and Conditions tab on both pages list the areas of validity and have helpful maps. Stations shown outside the valid area on these maps are valid - which can be checked by looking at the list. e.g. The Central Bohemia Ticket validity includes timetable routes "172, 173, 174, 200 ZdicePísek". This means that it is valid on the entire route of timetables 172, 173 and 174, along with Zdice to Pisek on table 200. Take a look at the bottom left of the Central Bohemia map to see this principle in action. The table numbers are shown on the maps.
Underneath the lists of local rover validities is a link to an excellent national map, which also shows the rover areas, including overlaps.
They used to do a bargain seven day ticket, but this was withdrawn a while back. Although outside the scope of your trip, in the summer, they often do a special summer rover. Last year, it was about £40 for 14 days during July/August!
Rover tickets are valid on pretty much all trains except open access operators. Travel by Pendolino requires a reservation to be purchased - this applies for all tickets.