Buying Out Siblings on Lake Property. . . Creative Ideas Needed!

[Jennifer Walsh]

Creative Ideas Needed! My Dad and his 2 siblings are each 1/3 owners of land on Lake Winnebago. The siblings seem to not want anything to do with the land, however, if we offer to buy them out I think they will then be interested and not want to sell their share. Any creative ideas on how we propose to buy them out without peaking their interest too much??
Also, whats the best way to determine the value of the land? Comps, tax assessments....?? Thank you Friends!