well, having lived in the IoW as a kid, and ridden & raced a pushbike round many times, and my dad going off to the TT to race every year, and latterly taking me to the TT to spectate ..... i always thought that the IoW would make a superb road race venue... my dad said it would never happen.
I could see a brilliant course there, even a mountain section, from Ventnor up St boniface down is a fabulus stretch of road up yo the highest point in the island.
but the island has a very well established tourist industry, and anything that might upset that will be resisted mightily , even if the organisers could guarantee similar numbers (or more) of the biking fraternity.
certainly the ferry costs and frequency would be a huge improvement on the IoM.
if the event were held late september early october (after skools go back) then i reckon maybe a 50/50 chance of at least a 1 event trial.
but the costs of policing, marshalling, road closing, and safety checks/fittings could be prohibitive.... certainly the police, local authority, tourism office etc will all have to be on board and enthusiastic ....
good luck to them... i'd even volunteer to help.... done well and with the whole island behind it, it could be a winner.... at worst it'll make the IoM (and the bloody steam packet Co) maybe take notice and buck theit ideas up.