A good do-it-yourself resource is Nolo Press (link below). They provide forums, publications, and a lawyer directory. Of course, it never hurts to speak with a local attorney experienced with nonprofit law.
**Disclosure: I have NO affiliation with Nolo Press.**
My response is informational only. It is not meant as legal advice and is not meant to create an attorney-client relationship.
A land trust is typically a revocable trust where the trustee holds title to the land. Your issue is not qualifying for a land trust.
Your issue may be the terms of your 501(c)(3) exemption if you already have one and if you don't the issue may be using an LLC for a charitable organization.
You don't need a "land trust", which is simply a fictitious name trust. If the LLC acquires the property, then the membership interests in the LLC can be given to the 501(c)(3). If the LLC that acquires the property has other assets that are not to be gifted to the 501(c)(3), then the LLC can contribute the acquired property to a new LLC and give the membership interests of that new LLC to the 501(c)(3). There is no need for a "land trust." If you need help, call.