Actually you CANNOT bike to seacrest's beach access (per the rules of the community that you have to go through). The tram is great - just give it a call. or its a short walk. However, there is a great beach access just past rosemary. Bike through rosemary and turn toward the beach just past the rosemary sign leaving town (near inlet beach).
You can get bikes in Peddlers pavilion. It's fun to explore rosemary - find the butterfly garden, kid playground, secret fountain. And don't miss biking on Alys' nature path!