Consider having the land trust turn into an irrevocable trust upon death of the seller if the seller is on the older side.

Have her do both a will and an irrevocable trust, with you getting the house. 

Quote from @Thomas Rutkowski: Seller sells to an irrevocable trust on a 30-year installment sales contract.

Asset Protection Trusts, Offshore Asset Protection Trusts (Cook Islands, Belize) and Irrevocable Trusts with a spendthrift clause are examples of how trusts can provide asset protection from lawsuits. 

Typically financing for investment properties are difficult if it's irrevocable.

Irrevocable trusts can be useful, but they’re a serious commitment.

Quote from @DeAnna McKillop-Lopez: I have been hearing a lot of people speaking about putting your holding LLC into an irrevocable trust.

Eventually this property will be transferred to my wife (through inheritance or irrevocable trust).

Typically are land trusts irrevocable or revocable trusts?

Just trying to learn, will an irrevocable statement (mixing another language like an Irrevocable Standby Letter of Credit / Irrevocable SBLC) or something similar of an instrument where both parties cannot take back what is in writing UNLESS another instrument is provided before the original is due.