Welcome to Eilan Sair
If you arrive in time, there is a ride-out by the local club "Hebriders" raising money for the "Macmillan Nurses" on Sat 19th May. Good for a whistle-stop tour of the Island.
As for accomadation, there is all sorts to suit your budget. Hotels, B&B, campsite's, Pubs with rooms (Carlton Bar, ask for Murry) also, weather permiting, lots of wild camping.
Bike security is not an issue on the Island, even in the main town.
Let me know youre arrival info and if you would like I can do a quick route plan for you (POI, Campsites, B&B).