Hi Chickpea. The train from London to Liverpool will take 2 and a half hours each way.
You can check out the times and which trains are direct - no changing - at
It's always cheaper to book well in advance !
It's over 400 miles round trip. And it's expensive at peak times. Around £200 return.
So if you get the 09:40 from Euston Station (London) to Lime St. Station Liverpool its only £39 with a change at Crewe. 20 minute change time.
And return at 19:48 Liv - Lon - Direct - £19.
Anything else ? Please ask