some of the clubs I have been part of, we typically give out gift cards to local businesses , be them restaurants, or gas stations, many of the clubs also extend offers to help land owners do work on there lands , from brush cleaning to other simple ways to be helpful to them
as a lot of the land owners we have worked with are now seniors and cannot do many things they used to, so they appreciate the offers and help , over just getting a gift card or likes!
we have also had member's that would bring them home made foods, ( home made Pies cakes, cookies , and assorted traditional holiday foods)which many again of the older land owners really seem to enjoy more than gift cards)
I know its not always possible or welcome, as these days, some folks are iffy on taking food from unknown folks,
but this has been a deal we do based on knowing certain land owners over the years! and what they like or prefer!, most when asked, will actually tell you , what they would rather, or at items, BOTH< pending how much trail they grant things, or also do for the clubs! !
knowing what some want more, really helps keep lands open IMO< as , when you invest time into getting to know land owners , you develop better relation ships, which keeps them open longer, or after miss hap's, as there more willing to work with you, after spending time together!, not always possible again, but worth doing when you can!
many older land owners are living alone and enjoy company!
as for marking maps, showing private lands, I think it wouldn;t hurt, but also, not sure it would do much to prevent things
the bigger issue, is many have NO clue where OPEN off trail riding is allowed, maybe them area's need to marked better on funded trail maps, to, maybe help others find them and not go off trail else where
but marking on maps is only half the deal, the area's them self need to be marked better maybe as well, ,. LARGER signs and such!