Disclaimer: In my post, no player-example is a noob. Consider every situation performed by a decently skilled player. 1vs1 is not in the equation, therefore an ambush is always considered. The rook in every scenario is a tower+hammer rook with 10%+ speed boost right off the start.
The way I see it, the hammer + tower rook are pretty rediculous. 1 rook can force an entire team to scratch their head until their hairs goes out. No other demigod can make other team this worried aside rook himself, then it became a contest of who got better rook player on their side.
My advise is to check your demigod match up before you start the game. If they got a rook(not a noob), and you have 0 ranged demigod, you are doomed to peril (very hard to win, but not impossible).
Oak imho is the best anti rook, with his ranged interrupt and sending minions non-stop to harass the rook across the towers. While the debuff on the already slow enough and make him take more damage is just perfectly suited against rook. With his shield at high level, he can recover to full health with heart of life in invincible mode.
Sedna got no business with rook aside watch and heal, and spam the minions who won't be very effective due to rook just getting more armor. (pounce is way too dangerous to use, due to tower and potential ambush with stuns) Your best bet is to conquer every where else to force rook to chase after you, which he can't do well at all.
QoT got a decent chance to harass rook due to range and sieging towers, but I haven't try QoT against rook enough to really say. Looks good on paper with all these range options + bramble shield.
Erebus shouldn have no trouble getting in and getting out. But you are way more open to stun ambush than oak is. Hence, your risk is much greater than that of the rook. In an attempt to assault rook with towers, erebus is probably your best friend next to oak.
TB can give alot of pain in the ass to rook, for pretty obvious reasons. Ice slow rook down too much for rook to do much, and if rook messed up, he is as good as dead. While fire TB can threaten him with fireball pretty easily, even if he is next to his towers.
Regulus is decent until rook stock up on high level armor, which will make regulus's arrow feel like tickles. Best idea is to coordinate with your team so that rook will never get his shinny new armor. Having mines setup in area rook is traveling to can ruin his game plan as well, because he would (hopefully) step on the mines before he setup the tower which force him to retreat or heal up.
UB has to play his game to the top level to have a chance at all. Your effectiveness against rook will continue to lower as the game progress. Biggest reasons are those towers. If you can catch a rook without his towers, you got a shot, but chance of you scoring a skill without a slow down is quite impossible; because the time you catch him without his towers are times that he is near his base. UB's poison is helpful in continue to deal damage to rook in retreat.
Although some demigod can take rook, the time you used on him is greatly wasted as he is difficult to take down. It is a much better idea to leave him alone and prey on his ally to keep them all lower level. If they all stay in a group, that rook speed is going to cut in eventually to allow you map domination.
Area that rook had setup towers are area that your team have to stay clear of, and if he assault your towers, be ready to all tele-ambush him (but know your priority before you tele-ambush). DO NOT GIVE HIM EASY KILLS, that is the true key against rook. Give him money and he will bang you all day.
Another method I wish to test is punisher's ward, as it reduce target demigod's mana. This can stop rook from setting up too many towers and spam hammer while at it. Best performed when there are 2 or more people doing it. Losing 800+ mana in a few sec is no joke.