TX landlord tenant act, tenant's right to terminate lease when rental property is for sale

Review your lease. Can you "legally" terminate your lease? There is nothing "illegal" in the criminal sense of terminating a lease. I assume you mean can you terminate your lease without being held liable for damages. Based on the information you have provided, it does not appear "constructive eviction" applies. The question ultimately will depend on whether the landlord has materially breached her obligations to you. The answer to that question can be answered by reviewing your lease. If you breach your lease and move out and the landlord is not found to have materially breached her obligations, you could be held liable for the remaining balance of the rent. The landlord does have an obligation to try and find another tenant to reduce her damages.

That being said, if you have not already done so, I would recommend talking to your land lord. The two of you can always come to some type of agreement, if it is not already spelled out in your lease. (e.g. hours to show the home, agreement to let you out of the lease, etc).