You seriously don't have to. Some things that aren't seen on YouTube, though, are in these links.

 

Alexandthomas Wiki- Although outdated, the Wiki provides background information on The Sodor Colony, especially.

DeviantArt- This art-sharing community provides some artwork, and even some promo pictures for Christmas 2012. Also has some pictures of fan-made ideas. Yeah.

Alexandthomas Music- The musical spin-off to Alexandthomas Productions has exclusive videos of piano-played themes. Will have more in the future!

Alexandthomas Productions- self-explanatory.

Google Plus- updates and stuff, plus some...uh...awesome pictures? Sure, why not.