LIke I said some of what he told me is pure speculation,but with the recent events such as the raid on Bin Laden`s compound security is bound to be much higher than normally would be for a Presidential visit-which is bonkers enough as it is.
I was surprised Baldonnel was mentioned as I thought the runways won`t be long enough,also the recent security breaches their won`t go unnoticed by US "Officals" as indeed would be the breaches in the past at Shannon.
Regarding an escort,it is standard practise for fighters to escort AF1 at least some point across the Atlantic,when Bush was here last,they picked up 4 F-15`s from Lakenheath NW of Donegal on the way in and a similar escort was waiting for them again when they departed.Its unlikely you would ever see the escorts,but they are there,mad as it may sound.
As Dave mentioned I think it is highly likely if they use Dublin,that the road will be closed off at some point,but as Canon John mentions if people turn up trying to get photos of the aircraft,the police are usually OK about it as long as you stay where they tell you,and there is a good few people there.If you were on your own,I`m sure you would be told to move on.