And that's the tough part...
Way too tough, because denominations are corporations, a religious business, not a true church whose head is Christ.
Baptists are doctrinally autonomous assemblies whose property is owned by voting members of the local church corporation. They can create, buy, sell, mortgage, insure their own property without answering to anyone else.
In Methodism, as in any episcopacy, the local church is not autonomous. The property used by the members is not their property. It is owned by the denomination, which is incorporated nationally and run by elected officers who may not even know any of the members.
They will have a hard time gaining ownership from the denomination if it chooses to keep all of it.
They would be wise to offer the denmination a fair price for the value of it, else the denomination may sell it to someone else, if the local assembly does not retain enough paying members to maintain the property.
Are these 100+ churches intending to unite to form their own non LGBTXYZ denomination incorporated in such a way the each local church body owns its own meeting place and other property?
As a group that large, they might well have bargaining power to force the national organization to sell them the property cheaply if they all intend to withdraw all at one time, and soon. Individually bargaining church by church, not a chance, I would surmise.
Furthermore, the bishop of the conference appoints ministers, then appoints them to a local assembly year by year, whether the congregation likes them or not. To go against him/her is to kiss your job goodbye, as well as employment with job security in any Methodist connection anywhere else.
Think twice before joining and investing in any local church that you don't know what their future conduct is going to be.