Is there a train station in Alnwick or where is the nearest station?
The nearest functional train station is Alnmouth. It's on the main line from London Kings Cross to Edinburgh. However, not all services stop there. You may neednto change on to a smaller local train (probably at Newcastle if traveling from London).
To get from Alnmouth to Alnwick you need a bus or taxi. I don't know if there is any car hire available. If you want to drive, the best solution would probably to hire a car in Newcastle.
A couple of good Taxi firms in alnwick are Yellow Taxi (yes it’s a yellow cab! )Also Sovereign there’s several more , but these are the 2 I’ve used . I wouldn’t rely on the arriva bus time to connect you from a train .
I wouldn’t rely on Google maps for up to date transport info.
No I agree , local knowledge can help !