Great to see all the positive comments. I have lived on the Isle of Wight for 40 years having come here on holiday the year before and loving it and have never regretted moving here. It is beautiful and has a slower pace of life yet much to do.
If Serendipity is coming over as part of a coach trip it is likely that there will be optional excursions and often these include Osborne House (fine for wheelchairs, staff will arrange a lift to upper floor). Yes, some places, such as Ventnor, are hilly but there are flat walks and most attractions, for example the model village and the craft village, are very accessible. We have a good bus service which includes some summer scenic routes such as over the Downs and the West Wight.
Good point above about June as the festival makes for a different experience especially around Newport and on the ferries with an extra 60,000 people added to our population of around 140,000.
Lovely cream teas and good food but referring to a previous post you are unlikely to find local strawberries these days. as sadly the commercial or self pick farms have closed. However, you may pick up the smell of garlic - we even have a festival for that!