Fun to think about all sorts of curious mayhem one might inflict on fools that unwittingly invade ones personal space and/or intrude on one's way of life. Like flies in a web.
I think the most effective way to promote ones views and is through alliance with and financial support of larger groups with political access and courtroom savvy. (IE: UFWDA, Blue Ribbon Coalition, regional assn's, NRA etc...) At the grassroots level, many of the good things accomplished are by individuals like us.
Some other important aspects are to actively practice good citizenship and stewardship. This includes Treading Lightly to the greatest extent possible, and being courteous/respectful to other users of public lands. Writing reasonably intelligent letters (to pols, govt. entities, media, etc...) that convey our side of the land-use issue in a rational manner may help to get the message out there too the public. Canned letters, emails, calls etc... likely only cause aggravation to the recipient.
The larger groups that oppose shared land use are amazingly well funded, and have lots of resources and celebrities to promote their side. Their goals seem very selfish to me, and offer little room for compromise. Unfortunately, all politics and the constant litigation in this country involves money for access and due process...
Unless we care to see all non-pedestrian off-pavement lifestyles (including 4x4s, quads, bikes, horses, bicycles, watercraft, personal aircraft etc...) marginalized to private property only, folks need to step up and be heard. Joining ranks and working out our interfaith differences while presenting a unified front for the 'multiple land use' cause. Blue Ribbon Coalition is attempting to do this with a lot of success. Although

is a club member of this group, members can individually join BRC for $10.00 for the first year ($20 per year following)
www.sharetrails.org

is an Association Member of United Four Wheel Drive Associations.
www.ufwda.org
I encourage all of you to join both of the above-mentioned organizations to help retain our access to public land, and to act responsibly while using it.
Thanks!