Cycle shops and businesses are the best places to start, as they may be willing to lend bikes to generate publicity and new customers. Local councils are worth approaching as they may be able to offer some staff time to help with an event or promotion if it fits with their existing plans or policies.
Businesses can be encouraged to offer pool bikes to their staff, to help reduce the need for costly company cars. Local shops could join together to provide cycle trailer loans, helping people to do more shopping at them and get home without the cost and hassle of driving. Waitrose, for example, loans cycle trailers for free at an increasing number of its branches: Waitrose cycle trailers.
Consider working with local charities working with people with disabilities, those with special needs and older people. They might not have considered the benefits not to mention fun of promoting different types of cycling.
Other parts of the toolkit that are relevant are training for safer cycling, improving cycle parking (for different types of cycle), maintaining cycles, community hubs and managing freight and lorries. Community hubs could be a good place to keep pool bikes and trailers and hire them out, while cycles can also help deliver freight for the last mile or so from a break-bulk point.