If you're going to succeed with AP Rammus top, you NEED your jungler to basically baby sit you. Event hen, this really isn't something I'd do to gain LP in a ranked game. Just try it out with your duo queue buddy in a normal when you're having a bad day. If you REALLY, REALLY want this to be somewhat viable, try to build a team comp around movement speed. E.G. Sivir, Ziliean, Hecarim, Rammus, Orianna. Something like this will guarantee that Rammus will be rolling in faster than sonic the hedgehog being shot out of a cannon.