Let them know that your club riders appreciate the support of dealer members and sponsors. Encourage them to participate in the education of new mountain bicyclists. Ask shops to distribute IMBA's Rules of the Trail and a membership form with every new bike sold. But be careful not to become so closely identified with a particular shop that other local retailers won't get involved. Government land management agencies have a responsibility to serve the general public, but often serve their perceived constituencies.
Bicyclists have every right to contact appointed officials to discuss trail cycling concerns.
You will find that most government employees are helpful and willing to work with you. You may find that they are worried about other users' reactions to mountain bikes. Be rational and well organized. As a rule, agencies move slowly. Be prepared and be patient.