Your question is possibly a little too vague to produce many useful answers.
Are you looking for accessible places to visit locally? (If so, what part of the country are you in? What type of places do you like visiting?). Are you looking for holidays in the UK (where you can tour the area by public transport)? Or are you looking for holidays abroad (where there are good public transport services)?
Please post again (on this thread), so that we can offer more help. To get you started though, I'll offer a few links:
1. The only site you need for rail travel within the UK is this one:
http://www.nationalrail.co.uk/
2. Bus timetables for the whole of the UK can be found here:
http://www.traveline.org.uk/index.htm
3. Rail timetables for the whole of Europe are brought together here:
http://reiseauskunft.bahn.de/bin/query.exe/en? newrequest=yes&protocol=http:&
Chris