You could always come to this year's MGP Dena! It's 18-31 August which covers practice for the first wheel then racing on the Monday, Wednesday and Friday of the second week. The weather is often better than the TT and the atmosphere is generally felt to be friendlier, with fewer big-name teams hogging the paddock and all the riders and supporters being open to approach. There are fewer spectators over (maybe not this year though!) so the ferries and hotels are more accessible. This makes matters easier but means there isn't such a party atmosphere downtown.... less hooligan riding too.

At this stage you may have to do some hunting for hotels and ferries but IMHO it's well worth the effort!