Both the Bombe replica and Colossus are now technically part of the National Museum of Computing rather than the Bletchley Park exhibits. But yes, check the opening times to ensure you can just see everything unless you live very nearby.
Colossus is more interesting not only from a Computing History point of view but also cryptographically.
Engima, though more famous, was a cryptographic cul-de-sac. It's the ultimate expression of a way of encrypting things that had already become more or less obsolete. The Bombes likewise are the extreme end of mechanical brute force attacks on such cryptography. They're both fiendishly clever, but in a way were already obsolete when WW2 broke out.
Lorenz though is in some sense an ancestor of cryptography you're using today. It's a stream cipher. The key is used to arrange for a stream of random-seeming bits to be generated, you XOR the bits with the message to get ciphertext, your opposite number generates the same stream with the same key, XORs the ciphertext and gets back the message.
Now, for Lorenz each symbol has only 5-bits whereas today we think in 8-bit bytes, but that's not a big deal. The general shape of the system is almost what you'd build today.
And so likewise Colossus is almost a modern computer. It was digital and electronic, and even programmable, but since the programming involves essentially taking the machine to pieces it's not quite a modern stored program digital computer. In practice Colossus served one purpose, to break Lorenz as part of the Ultra secret. As Bletchley cryptanalysts understood more about Lorenz they could reprogram Colossus to try new things.