Bicycling to the Alameda Ferry is a wonderful way to get to downtown San Francisco. You can take your bicycle on BART to and from many destinations. Generally, a bit of research may be required. Dressing up for work can be handled by taking advantage of shower facilities that more and more employers are offering, or simply bringing a change of clothes or not pushing yourself too hard. A practice ride on a weekend may be all that's required to get a sense of how much of a concern this need be.
Safety is an important consideration to everybody.
We are fortunate that Alameda is a fairly laid-back town, but it pays to be cautious. Streets with less traffic or marked bike lanes are preferred over heavily travelled streets such as Webster. For instance, Pacific is a better street to bike on than Buena Vista or Lincoln. The importance of wearing a bicycle helmet, and wearing it properly , cannot be overstated. If you ride when it's dark, lighting is important and is required by law.