Partial off-peak return?

[Envy123]

I'll be making the following journey on Thursday:

-St Pancras to St Alban's City, then walk to my meeting place which takes place at 2pm
-Then, I will come back home 3-4pm from St Alban's City to Mill Hill Broadway (which has a bus that takes me back home - this is quickest)

What is the best value ticket for this journey? I have no railcards. I've been thinking about the possible options:

-Buying an off-peak return from St Pancras to St Alban's, but stopping short at Mill Hill Broadway on the way back.
-Get the Key Smartcard and use KeyGo (as I will travel from home to St Alban's and Hatfield quite a lot) - though I'm not sure how the pricing would work in this case. And I live within the Travelcard zones so activating the Key before my journey may not be possible.

Any help would be appreciated.

 

[Romilly]

£12.70 St Pancras to St Albans day return is not only cheaper than a St Pancras-Mill Hill Broadway single coupled with a Mill Hill Bwy to St Albans return, but also allows you on the outward journey to get a train that doesn't stop at Mill Hill Broadway.

 

[Envy123]

£12.70 St Pancras to St Albans day return is not only cheaper than a St Pancras-Mill Hill Broadway single coupled with a Mill Hill Bwy to St Albans return, but also allows you on the outward journey to get a train that doesn't stop at Mill Hill Broadway.

Thank you - will do just that.